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• How to Write a Literature Review | Guide, Examples, & Templates

How to Write a Literature Review | Guide, Examples, & Templates

Published on January 2, 2023 by Shona McCombes . Revised on September 11, 2023.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research that you can later apply to your paper, thesis, or dissertation topic .

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates, and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarize sources—it analyzes, synthesizes , and critically evaluates to give a clear picture of the state of knowledge on the subject.

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Table of contents

What is the purpose of a literature review, examples of literature reviews, step 1 – search for relevant literature, step 2 – evaluate and select sources, step 3 – identify themes, debates, and gaps, step 4 – outline your literature review’s structure, step 5 – write your literature review, free lecture slides, other interesting articles, frequently asked questions, introduction.

• Quick Run-through
• Step 1 & 2

When you write a thesis , dissertation , or research paper , you will likely have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and its scholarly context
• Develop a theoretical framework and methodology for your research
• Position your work in relation to other researchers and theorists
• Show how your research addresses a gap or contributes to a debate
• Evaluate the current state of research and demonstrate your knowledge of the scholarly debates around your topic.

Writing literature reviews is a particularly important skill if you want to apply for graduate school or pursue a career in research. We’ve written a step-by-step guide that you can follow below.

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Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research problem and questions .

Make a list of keywords

Start by creating a list of keywords related to your research question. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list as you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some useful databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can also use boolean operators to help narrow down your search.

Make sure to read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

You likely won’t be able to read absolutely everything that has been written on your topic, so it will be necessary to evaluate which sources are most relevant to your research question.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models, and methods?
• Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible , and make sure you read any landmark studies and major theories in your field of research.

You can use our template to summarize and evaluate sources you’re thinking about using. Click on either button below to download.

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It is important to keep track of your sources with citations to avoid plagiarism . It can be helpful to make an annotated bibliography , where you compile full citation information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

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To begin organizing your literature review’s argument and structure, be sure you understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly visual platforms like Instagram and Snapchat—this is a gap that you could address in your own research.

There are various approaches to organizing the body of a literature review. Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarizing sources in order.

Try to analyze patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organize your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text , your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, you can follow these tips:

• Summarize and synthesize: give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: don’t just paraphrase other researchers — add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically evaluate: mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: use transition words and topic sentences to draw connections, comparisons and contrasts

In the conclusion, you should summarize the key findings you have taken from the literature and emphasize their significance.

When you’ve finished writing and revising your literature review, don’t forget to proofread thoroughly before submitting. Not a language expert? Check out Scribbr’s professional proofreading services !

This article has been adapted into lecture slides that you can use to teach your students about writing a literature review.

Scribbr slides are free to use, customize, and distribute for educational purposes.

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If you want to know more about the research process , methodology , research bias , or statistics , make sure to check out some of our other articles with explanations and examples.

• Sampling methods
• Simple random sampling
• Stratified sampling
• Cluster sampling
• Likert scales
• Reproducibility

 Statistics

• Null hypothesis
• Statistical power
• Probability distribution
• Effect size
• Poisson distribution

Research bias

• Optimism bias
• Cognitive bias
• Implicit bias
• Hawthorne effect
• Anchoring bias
• Explicit bias

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarize yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your thesis or dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

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What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

• What is the purpose of literature review? 
• a. Habitat Loss and Species Extinction: 
• b. Range Shifts and Phenological Changes: 
• c. Ocean Acidification and Coral Reefs: 
• d. Adaptive Strategies and Conservation Efforts: 

How to write a good literature review 

• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• How to write a literature review faster with Paperpal? 
• Frequently asked questions 

What is a literature review?

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

What is the purpose of literature review?

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

1. Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 

2. Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field. 

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3. Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 

4. Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 

5. Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 

6. Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

a. Habitat Loss and Species Extinction:

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

b. Range Shifts and Phenological Changes:

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

c. Ocean Acidification and Coral Reefs:

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

d. Adaptive Strategies and Conservation Efforts:

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

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Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

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Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

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How to write a literature review faster with Paperpal?

Paperpal, an AI writing assistant, integrates powerful academic search capabilities within its writing platform. With the Research feature, you get 100% factual insights, with citations backed by 250M+ verified research articles, directly within your writing interface with the option to save relevant references in your Citation Library. By eliminating the need to switch tabs to find answers to all your research questions, Paperpal saves time and helps you stay focused on your writing.   

Here’s how to use the Research feature:  

• Ask a question: Get started with a new document on paperpal.com. Click on the “Research” feature and type your question in plain English. Paperpal will scour over 250 million research articles, including conference papers and preprints, to provide you with accurate insights and citations. 
• Review and Save: Paperpal summarizes the information, while citing sources and listing relevant reads. You can quickly scan the results to identify relevant references and save these directly to your built-in citations library for later access. 
• Cite with Confidence: Paperpal makes it easy to incorporate relevant citations and references into your writing, ensuring your arguments are well-supported by credible sources. This translates to a polished, well-researched literature review. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a good literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. By combining effortless research with an easy citation process, Paperpal Research streamlines the literature review process and empowers you to write faster and with more confidence. Try Paperpal Research now and see for yourself.  

Frequently asked questions

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

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Libraries | Research Guides

Literature reviews, what is a literature review, learning more about how to do a literature review.

• Planning the Review
• The Research Question
• Choosing Where to Search
• Organizing the Review
• Writing the Review

A literature review is a review and synthesis of existing research on a topic or research question. A literature review is meant to analyze the scholarly literature, make connections across writings and identify strengths, weaknesses, trends, and missing conversations. A literature review should address different aspects of a topic as it relates to your research question. A literature review goes beyond a description or summary of the literature you have read. 

• Sage Research Methods Core This link opens in a new window SAGE Research Methods supports research at all levels by providing material to guide users through every step of the research process. SAGE Research Methods is the ultimate methods library with more than 1000 books, reference works, journal articles, and instructional videos by world-leading academics from across the social sciences, including the largest collection of qualitative methods books available online from any scholarly publisher. – Publisher

• Next: Planning the Review >>
• Last Updated: Jul 8, 2024 11:22 AM
• URL: https://libguides.northwestern.edu/literaturereviews

• UConn Library
• Literature Review: The What, Why and How-to Guide
• Introduction

Literature Review: The What, Why and How-to Guide — Introduction

• Getting Started
• How to Pick a Topic
• Strategies to Find Sources
• Evaluating Sources & Lit. Reviews
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings

What are Literature Reviews?

So, what is a literature review? "A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries." Taylor, D.  The literature review: A few tips on conducting it . University of Toronto Health Sciences Writing Centre.

Goals of Literature Reviews

What are the goals of creating a Literature Review?  A literature could be written to accomplish different aims:

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 

Baumeister, R. F., & Leary, M. R. (1997). Writing narrative literature reviews .  Review of General Psychology , 1 (3), 311-320.

What kinds of sources require a Literature Review?

• A research paper assigned in a course
• A thesis or dissertation
• A grant proposal
• An article intended for publication in a journal

All these instances require you to collect what has been written about your research topic so that you can demonstrate how your own research sheds new light on the topic.

Types of Literature Reviews

What kinds of literature reviews are written?

Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified. The review ends with a conclusion section which summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.

• Example : Predictors and Outcomes of U.S. Quality Maternity Leave: A Review and Conceptual Framework:  10.1177/08948453211037398  

Systematic review : "The authors of a systematic review use a specific procedure to search the research literature, select the studies to include in their review, and critically evaluate the studies they find." (p. 139). Nelson, L. K. (2013). Research in Communication Sciences and Disorders . Plural Publishing.

• Example : The effect of leave policies on increasing fertility: a systematic review:  10.1057/s41599-022-01270-w

Meta-analysis : "Meta-analysis is a method of reviewing research findings in a quantitative fashion by transforming the data from individual studies into what is called an effect size and then pooling and analyzing this information. The basic goal in meta-analysis is to explain why different outcomes have occurred in different studies." (p. 197). Roberts, M. C., & Ilardi, S. S. (2003). Handbook of Research Methods in Clinical Psychology . Blackwell Publishing.

• Example : Employment Instability and Fertility in Europe: A Meta-Analysis:  10.1215/00703370-9164737

Meta-synthesis : "Qualitative meta-synthesis is a type of qualitative study that uses as data the findings from other qualitative studies linked by the same or related topic." (p.312). Zimmer, L. (2006). Qualitative meta-synthesis: A question of dialoguing with texts .  Journal of Advanced Nursing , 53 (3), 311-318.

• Example : Women’s perspectives on career successes and barriers: A qualitative meta-synthesis:  10.1177/05390184221113735

Literature Reviews in the Health Sciences

• UConn Health subject guide on systematic reviews Explanation of the different review types used in health sciences literature as well as tools to help you find the right review type
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Writing a Literature Review

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A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

Research Methods

• Getting Started
• Literature Review Research
• Research Design
• Research Design By Discipline
• SAGE Research Methods
• Teaching with SAGE Research Methods

Literature Review

• What is a Literature Review?
• What is NOT a Literature Review?
• Purposes of a Literature Review
• Types of Literature Reviews
• Literature Reviews vs. Systematic Reviews
• Systematic vs. Meta-Analysis

Literature Review  is a comprehensive survey of the works published in a particular field of study or line of research, usually over a specific period of time, in the form of an in-depth, critical bibliographic essay or annotated list in which attention is drawn to the most significant works.

Also, we can define a literature review as the collected body of scholarly works related to a topic:

• Summarizes and analyzes previous research relevant to a topic
• Includes scholarly books and articles published in academic journals
• Can be an specific scholarly paper or a section in a research paper

The objective of a Literature Review is to find previous published scholarly works relevant to an specific topic

• Help gather ideas or information
• Keep up to date in current trends and findings
• Help develop new questions

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Helps focus your own research questions or problems
• Discovers relationships between research studies/ideas.
• Suggests unexplored ideas or populations
• Identifies major themes, concepts, and researchers on a topic.
• Tests assumptions; may help counter preconceived ideas and remove unconscious bias.
• Identifies critical gaps, points of disagreement, or potentially flawed methodology or theoretical approaches.
• Indicates potential directions for future research.

All content in this section is from Literature Review Research from Old Dominion University 

Keep in mind the following, a literature review is NOT:

Not an essay 

Not an annotated bibliography  in which you summarize each article that you have reviewed.  A literature review goes beyond basic summarizing to focus on the critical analysis of the reviewed works and their relationship to your research question.

Not a research paper   where you select resources to support one side of an issue versus another.  A lit review should explain and consider all sides of an argument in order to avoid bias, and areas of agreement and disagreement should be highlighted.

A literature review serves several purposes. For example, it

• provides thorough knowledge of previous studies; introduces seminal works.
• helps focus one’s own research topic.
• identifies a conceptual framework for one’s own research questions or problems; indicates potential directions for future research.
• suggests previously unused or underused methodologies, designs, quantitative and qualitative strategies.
• identifies gaps in previous studies; identifies flawed methodologies and/or theoretical approaches; avoids replication of mistakes.
• helps the researcher avoid repetition of earlier research.
• suggests unexplored populations.
• determines whether past studies agree or disagree; identifies controversy in the literature.
• tests assumptions; may help counter preconceived ideas and remove unconscious bias.

As Kennedy (2007) notes*, it is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the original studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally that become part of the lore of field. In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews.

Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are several approaches to how they can be done, depending upon the type of analysis underpinning your study. Listed below are definitions of types of literature reviews:

Argumentative Review      This form examines literature selectively in order to support or refute an argument, deeply imbedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to to make summary claims of the sort found in systematic reviews.

Integrative Review      Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication.

Historical Review      Few things rest in isolation from historical precedent. Historical reviews are focused on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review      A review does not always focus on what someone said [content], but how they said it [method of analysis]. This approach provides a framework of understanding at different levels (i.e. those of theory, substantive fields, research approaches and data collection and analysis techniques), enables researchers to draw on a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection and data analysis, and helps highlight many ethical issues which we should be aware of and consider as we go through our study.

Systematic Review      This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyse data from the studies that are included in the review. Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?"

Theoretical Review      The purpose of this form is to concretely examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review help establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

* Kennedy, Mary M. "Defining a Literature."  Educational Researcher  36 (April 2007): 139-147.

All content in this section is from The Literature Review created by Dr. Robert Larabee USC

Robinson, P. and Lowe, J. (2015),  Literature reviews vs systematic reviews.  Australian and New Zealand Journal of Public Health, 39: 103-103. doi: 10.1111/1753-6405.12393

What's in the name? The difference between a Systematic Review and a Literature Review, and why it matters . By Lynn Kysh from University of Southern California

Systematic review or meta-analysis?

A  systematic review  answers a defined research question by collecting and summarizing all empirical evidence that fits pre-specified eligibility criteria.

A  meta-analysis  is the use of statistical methods to summarize the results of these studies.

Systematic reviews, just like other research articles, can be of varying quality. They are a significant piece of work (the Centre for Reviews and Dissemination at York estimates that a team will take 9-24 months), and to be useful to other researchers and practitioners they should have:

• clearly stated objectives with pre-defined eligibility criteria for studies
• explicit, reproducible methodology
• a systematic search that attempts to identify all studies
• assessment of the validity of the findings of the included studies (e.g. risk of bias)
• systematic presentation, and synthesis, of the characteristics and findings of the included studies

Not all systematic reviews contain meta-analysis. 

Meta-analysis is the use of statistical methods to summarize the results of independent studies. By combining information from all relevant studies, meta-analysis can provide more precise estimates of the effects of health care than those derived from the individual studies included within a review.  More information on meta-analyses can be found in  Cochrane Handbook, Chapter 9 .

A meta-analysis goes beyond critique and integration and conducts secondary statistical analysis on the outcomes of similar studies.  It is a systematic review that uses quantitative methods to synthesize and summarize the results.

An advantage of a meta-analysis is the ability to be completely objective in evaluating research findings.  Not all topics, however, have sufficient research evidence to allow a meta-analysis to be conducted.  In that case, an integrative review is an appropriate strategy. 

Some of the content in this section is from Systematic reviews and meta-analyses: step by step guide created by Kate McAllister.

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Research Methods and Design

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Literature Review

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A literature review is a discussion of the literature (aka. the "research" or "scholarship") surrounding a certain topic. A good literature review doesn't simply summarize the existing material, but provides thoughtful synthesis and analysis. The purpose of a literature review is to orient your own work within an existing body of knowledge. A literature review may be written as a standalone piece or be included in a larger body of work.

You can read more about literature reviews, what they entail, and how to write one, using the resources below. 

Am I the only one struggling to write a literature review?

Dr. Zina O'Leary explains the misconceptions and struggles students often have with writing a literature review. She also provides step-by-step guidance on writing a persuasive literature review.

An Introduction to Literature Reviews

Dr. Eric Jensen, Professor of Sociology at the University of Warwick, and Dr. Charles Laurie, Director of Research at Verisk Maplecroft, explain how to write a literature review, and why researchers need to do so. Literature reviews can be stand-alone research or part of a larger project. They communicate the state of academic knowledge on a given topic, specifically detailing what is still unknown.

This is the first video in a whole series about literature reviews. You can find the rest of the series in our SAGE database, Research Methods:

Videos covering research methods and statistics

Identify Themes and Gaps in Literature (with real examples) | Scribbr

Finding connections between sources is key to organizing the arguments and structure of a good literature review. In this video, you'll learn how to identify themes, debates, and gaps between sources, using examples from real papers.

4 Tips for Writing a Literature Review's Intro, Body, and Conclusion | Scribbr

While each review will be unique in its structure--based on both the existing body of both literature and the overall goals of your own paper, dissertation, or research--this video from Scribbr does a good job simplifying the goals of writing a literature review for those who are new to the process. In this video, you’ll learn what to include in each section, as well as 4 tips for the main body illustrated with an example.

• Literature Review This chapter in SAGE's Encyclopedia of Research Design describes the types of literature reviews and scientific standards for conducting literature reviews.
• UNC Writing Center: Literature Reviews This handout from the Writing Center at UNC will explain what literature reviews are and offer insights into the form and construction of literature reviews in the humanities, social sciences, and sciences.
• Purdue OWL: Writing a Literature Review The overview of literature reviews comes from Purdue's Online Writing Lab. It explains the basic why, what, and how of writing a literature review.

Organizational Tools for Literature Reviews

One of the most daunting aspects of writing a literature review is organizing your research. There are a variety of strategies that you can use to help you in this task. We've highlighted just a few ways writers keep track of all that information! You can use a combination of these tools or come up with your own organizational process. The key is choosing something that works with your own learning style.

Citation Managers

Citation managers are great tools, in general, for organizing research, but can be especially helpful when writing a literature review. You can keep all of your research in one place, take notes, and organize your materials into different folders or categories. Read more about citations managers here:

• Manage Citations & Sources

Concept Mapping

Some writers use concept mapping (sometimes called flow or bubble charts or "mind maps") to help them visualize the ways in which the research they found connects.

There is no right or wrong way to make a concept map. There are a variety of online tools that can help you create a concept map or you can simply put pen to paper. To read more about concept mapping, take a look at the following help guides:

• Using Concept Maps From Williams College's guide, Literature Review: A Self-guided Tutorial

Synthesis Matrix

A synthesis matrix is is a chart you can use to help you organize your research into thematic categories. By organizing your research into a matrix, like the examples below, can help you visualize the ways in which your sources connect. 

• Walden University Writing Center: Literature Review Matrix Find a variety of literature review matrix examples and templates from Walden University.
• Writing A Literature Review and Using a Synthesis Matrix An example synthesis matrix created by NC State University Writing and Speaking Tutorial Service Tutors. If you would like a copy of this synthesis matrix in a different format, like a Word document, please ask a librarian. CC-BY-SA 3.0
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Literature Review as a Research Methodology: An overview and guidelines

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Research Methods: Literature Reviews

• Annotated Bibliographies
• Literature Reviews
• Scoping Reviews
• Systematic Reviews
• Scholarship of Teaching and Learning
• Persuasive Arguments
• Subject Specific Methodology

A literature review involves researching, reading, analyzing, evaluating, and summarizing scholarly literature (typically journals and articles) about a specific topic. The results of a literature review may be an entire report or article OR may be part of a article, thesis, dissertation, or grant proposal. A literature review helps the author learn about the history and nature of their topic, and identify research gaps and problems.

Steps & Elements

Problem formulation

• Determine your topic and its components by asking a question
• Research: locate literature related to your topic to identify the gap(s) that can be addressed
• Read: read the articles or other sources of information
• Analyze: assess the findings for relevancy
• Evaluating: determine how the article are relevant to your research and what are the key findings
• Synthesis: write about the key findings and how it is relevant to your research

Elements of a Literature Review

• Summarize subject, issue or theory under consideration, along with objectives of the review
• Divide works under review into categories (e.g. those in support of a particular position, those against, those offering alternative theories entirely)
• Explain how each work is similar to and how it varies from the others
• Conclude which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of an area of research

Writing a Literature Review Resources

• How to Write a Literature Review From the Wesleyan University Library
• Write a Literature Review From the University of California Santa Cruz Library. A Brief overview of a literature review, includes a list of stages for writing a lit review.
• Literature Reviews From the University of North Carolina Writing Center. Detailed information about writing a literature review.
• Undertaking a literature review: a step-by-step approach Cronin, P., Ryan, F., & Coughan, M. (2008). Undertaking a literature review: A step-by-step approach. British Journal of Nursing, 17(1), p.38-43

Literature Review Tutorial

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Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.

Handbook of eHealth Evaluation: An Evidence-based Approach [Internet].

Chapter 9 methods for literature reviews.

Guy Paré and Spyros Kitsiou .

9.1. Introduction

Literature reviews play a critical role in scholarship because science remains, first and foremost, a cumulative endeavour ( vom Brocke et al., 2009 ). As in any academic discipline, rigorous knowledge syntheses are becoming indispensable in keeping up with an exponentially growing eHealth literature, assisting practitioners, academics, and graduate students in finding, evaluating, and synthesizing the contents of many empirical and conceptual papers. Among other methods, literature reviews are essential for: (a) identifying what has been written on a subject or topic; (b) determining the extent to which a specific research area reveals any interpretable trends or patterns; (c) aggregating empirical findings related to a narrow research question to support evidence-based practice; (d) generating new frameworks and theories; and (e) identifying topics or questions requiring more investigation ( Paré, Trudel, Jaana, & Kitsiou, 2015 ).

Literature reviews can take two major forms. The most prevalent one is the “literature review” or “background” section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses ( Sylvester, Tate, & Johnstone, 2013 ). It may also provide a theoretical foundation for the proposed study, substantiate the presence of the research problem, justify the research as one that contributes something new to the cumulated knowledge, or validate the methods and approaches for the proposed study ( Hart, 1998 ; Levy & Ellis, 2006 ).

The second form of literature review, which is the focus of this chapter, constitutes an original and valuable work of research in and of itself ( Paré et al., 2015 ). Rather than providing a base for a researcher’s own work, it creates a solid starting point for all members of the community interested in a particular area or topic ( Mulrow, 1987 ). The so-called “review article” is a journal-length paper which has an overarching purpose to synthesize the literature in a field, without collecting or analyzing any primary data ( Green, Johnson, & Adams, 2006 ).

When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices ( Paré et al., 2015 ). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies ( Cooper, 1988 ; Rowe, 2014 ). Scholars who track and gauge the impact of articles have found that review papers are cited and downloaded more often than any other type of published article ( Cronin, Ryan, & Coughlan, 2008 ; Montori, Wilczynski, Morgan, Haynes, & Hedges, 2003 ; Patsopoulos, Analatos, & Ioannidis, 2005 ). The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources ( Cronin et al., 2008 ). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one’s academic community ( Paré et al., 2015 ; Petticrew & Roberts, 2006 ). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type.

The main objectives of this chapter are fourfold: (a) to provide an overview of the major steps and activities involved in conducting a stand-alone literature review; (b) to describe and contrast the different types of review articles that can contribute to the eHealth knowledge base; (c) to illustrate each review type with one or two examples from the eHealth literature; and (d) to provide a series of recommendations for prospective authors of review articles in this domain.

9.2. Overview of the Literature Review Process and Steps

As explained in Templier and Paré (2015) , there are six generic steps involved in conducting a review article:

• formulating the research question(s) and objective(s),
• searching the extant literature,
• screening for inclusion,
• assessing the quality of primary studies,
• extracting data, and
• analyzing data.

Although these steps are presented here in sequential order, one must keep in mind that the review process can be iterative and that many activities can be initiated during the planning stage and later refined during subsequent phases ( Finfgeld-Connett & Johnson, 2013 ; Kitchenham & Charters, 2007 ).

Formulating the research question(s) and objective(s): As a first step, members of the review team must appropriately justify the need for the review itself ( Petticrew & Roberts, 2006 ), identify the review’s main objective(s) ( Okoli & Schabram, 2010 ), and define the concepts or variables at the heart of their synthesis ( Cooper & Hedges, 2009 ; Webster & Watson, 2002 ). Importantly, they also need to articulate the research question(s) they propose to investigate ( Kitchenham & Charters, 2007 ). In this regard, we concur with Jesson, Matheson, and Lacey (2011) that clearly articulated research questions are key ingredients that guide the entire review methodology; they underscore the type of information that is needed, inform the search for and selection of relevant literature, and guide or orient the subsequent analysis. Searching the extant literature: The next step consists of searching the literature and making decisions about the suitability of material to be considered in the review ( Cooper, 1988 ). There exist three main coverage strategies. First, exhaustive coverage means an effort is made to be as comprehensive as possible in order to ensure that all relevant studies, published and unpublished, are included in the review and, thus, conclusions are based on this all-inclusive knowledge base. The second type of coverage consists of presenting materials that are representative of most other works in a given field or area. Often authors who adopt this strategy will search for relevant articles in a small number of top-tier journals in a field ( Paré et al., 2015 ). In the third strategy, the review team concentrates on prior works that have been central or pivotal to a particular topic. This may include empirical studies or conceptual papers that initiated a line of investigation, changed how problems or questions were framed, introduced new methods or concepts, or engendered important debate ( Cooper, 1988 ). Screening for inclusion: The following step consists of evaluating the applicability of the material identified in the preceding step ( Levy & Ellis, 2006 ; vom Brocke et al., 2009 ). Once a group of potential studies has been identified, members of the review team must screen them to determine their relevance ( Petticrew & Roberts, 2006 ). A set of predetermined rules provides a basis for including or excluding certain studies. This exercise requires a significant investment on the part of researchers, who must ensure enhanced objectivity and avoid biases or mistakes. As discussed later in this chapter, for certain types of reviews there must be at least two independent reviewers involved in the screening process and a procedure to resolve disagreements must also be in place ( Liberati et al., 2009 ; Shea et al., 2009 ). Assessing the quality of primary studies: In addition to screening material for inclusion, members of the review team may need to assess the scientific quality of the selected studies, that is, appraise the rigour of the research design and methods. Such formal assessment, which is usually conducted independently by at least two coders, helps members of the review team refine which studies to include in the final sample, determine whether or not the differences in quality may affect their conclusions, or guide how they analyze the data and interpret the findings ( Petticrew & Roberts, 2006 ). Ascribing quality scores to each primary study or considering through domain-based evaluations which study components have or have not been designed and executed appropriately makes it possible to reflect on the extent to which the selected study addresses possible biases and maximizes validity ( Shea et al., 2009 ). Extracting data: The following step involves gathering or extracting applicable information from each primary study included in the sample and deciding what is relevant to the problem of interest ( Cooper & Hedges, 2009 ). Indeed, the type of data that should be recorded mainly depends on the initial research questions ( Okoli & Schabram, 2010 ). However, important information may also be gathered about how, when, where and by whom the primary study was conducted, the research design and methods, or qualitative/quantitative results ( Cooper & Hedges, 2009 ). Analyzing and synthesizing data : As a final step, members of the review team must collate, summarize, aggregate, organize, and compare the evidence extracted from the included studies. The extracted data must be presented in a meaningful way that suggests a new contribution to the extant literature ( Jesson et al., 2011 ). Webster and Watson (2002) warn researchers that literature reviews should be much more than lists of papers and should provide a coherent lens to make sense of extant knowledge on a given topic. There exist several methods and techniques for synthesizing quantitative (e.g., frequency analysis, meta-analysis) and qualitative (e.g., grounded theory, narrative analysis, meta-ethnography) evidence ( Dixon-Woods, Agarwal, Jones, Young, & Sutton, 2005 ; Thomas & Harden, 2008 ).

9.3. Types of Review Articles and Brief Illustrations

EHealth researchers have at their disposal a number of approaches and methods for making sense out of existing literature, all with the purpose of casting current research findings into historical contexts or explaining contradictions that might exist among a set of primary research studies conducted on a particular topic. Our classification scheme is largely inspired from Paré and colleagues’ (2015) typology. Below we present and illustrate those review types that we feel are central to the growth and development of the eHealth domain.

9.3.1. Narrative Reviews

The narrative review is the “traditional” way of reviewing the extant literature and is skewed towards a qualitative interpretation of prior knowledge ( Sylvester et al., 2013 ). Put simply, a narrative review attempts to summarize or synthesize what has been written on a particular topic but does not seek generalization or cumulative knowledge from what is reviewed ( Davies, 2000 ; Green et al., 2006 ). Instead, the review team often undertakes the task of accumulating and synthesizing the literature to demonstrate the value of a particular point of view ( Baumeister & Leary, 1997 ). As such, reviewers may selectively ignore or limit the attention paid to certain studies in order to make a point. In this rather unsystematic approach, the selection of information from primary articles is subjective, lacks explicit criteria for inclusion and can lead to biased interpretations or inferences ( Green et al., 2006 ). There are several narrative reviews in the particular eHealth domain, as in all fields, which follow such an unstructured approach ( Silva et al., 2015 ; Paul et al., 2015 ).

Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research ( Cronin et al., 2008 ). Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature ( Green et al., 2006 ). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues ( Green et al., 2006 ).

Recently, there have been several efforts to introduce more rigour in narrative reviews that will elucidate common pitfalls and bring changes into their publication standards. Information systems researchers, among others, have contributed to advancing knowledge on how to structure a “traditional” review. For instance, Levy and Ellis (2006) proposed a generic framework for conducting such reviews. Their model follows the systematic data processing approach comprised of three steps, namely: (a) literature search and screening; (b) data extraction and analysis; and (c) writing the literature review. They provide detailed and very helpful instructions on how to conduct each step of the review process. As another methodological contribution, vom Brocke et al. (2009) offered a series of guidelines for conducting literature reviews, with a particular focus on how to search and extract the relevant body of knowledge. Last, Bandara, Miskon, and Fielt (2011) proposed a structured, predefined and tool-supported method to identify primary studies within a feasible scope, extract relevant content from identified articles, synthesize and analyze the findings, and effectively write and present the results of the literature review. We highly recommend that prospective authors of narrative reviews consult these useful sources before embarking on their work.

Darlow and Wen (2015) provide a good example of a highly structured narrative review in the eHealth field. These authors synthesized published articles that describe the development process of mobile health ( m-health ) interventions for patients’ cancer care self-management. As in most narrative reviews, the scope of the research questions being investigated is broad: (a) how development of these systems are carried out; (b) which methods are used to investigate these systems; and (c) what conclusions can be drawn as a result of the development of these systems. To provide clear answers to these questions, a literature search was conducted on six electronic databases and Google Scholar . The search was performed using several terms and free text words, combining them in an appropriate manner. Four inclusion and three exclusion criteria were utilized during the screening process. Both authors independently reviewed each of the identified articles to determine eligibility and extract study information. A flow diagram shows the number of studies identified, screened, and included or excluded at each stage of study selection. In terms of contributions, this review provides a series of practical recommendations for m-health intervention development.

9.3.2. Descriptive or Mapping Reviews

The primary goal of a descriptive review is to determine the extent to which a body of knowledge in a particular research topic reveals any interpretable pattern or trend with respect to pre-existing propositions, theories, methodologies or findings ( King & He, 2005 ; Paré et al., 2015 ). In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies ( Petersen, Vakkalanka, & Kuzniarz, 2015 ). Indeed, structured search methods are used to form a representative sample of a larger group of published works ( Paré et al., 2015 ). Further, authors of descriptive reviews extract from each study certain characteristics of interest, such as publication year, research methods, data collection techniques, and direction or strength of research outcomes (e.g., positive, negative, or non-significant) in the form of frequency analysis to produce quantitative results ( Sylvester et al., 2013 ). In essence, each study included in a descriptive review is treated as the unit of analysis and the published literature as a whole provides a database from which the authors attempt to identify any interpretable trends or draw overall conclusions about the merits of existing conceptualizations, propositions, methods or findings ( Paré et al., 2015 ). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain ( King & He, 2005 ).

In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin (2008) as mapping reviews . Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped.

An example of this approach in the eHealth domain is offered by DeShazo, Lavallie, and Wolf (2009). The purpose of this descriptive or mapping review was to characterize publication trends in the medical informatics literature over a 20-year period (1987 to 2006). To achieve this ambitious objective, the authors performed a bibliometric analysis of medical informatics citations indexed in medline using publication trends, journal frequencies, impact factors, Medical Subject Headings (MeSH) term frequencies, and characteristics of citations. Findings revealed that there were over 77,000 medical informatics articles published during the covered period in numerous journals and that the average annual growth rate was 12%. The MeSH term analysis also suggested a strong interdisciplinary trend. Finally, average impact scores increased over time with two notable growth periods. Overall, patterns in research outputs that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline (DeShazo et al., 2009).

9.3.3. Scoping Reviews

Scoping reviews attempt to provide an initial indication of the potential size and nature of the extant literature on an emergent topic (Arksey & O’Malley, 2005; Daudt, van Mossel, & Scott, 2013 ; Levac, Colquhoun, & O’Brien, 2010). A scoping review may be conducted to examine the extent, range and nature of research activities in a particular area, determine the value of undertaking a full systematic review (discussed next), or identify research gaps in the extant literature ( Paré et al., 2015 ). In line with their main objective, scoping reviews usually conclude with the presentation of a detailed research agenda for future works along with potential implications for both practice and research.

Unlike narrative and descriptive reviews, the whole point of scoping the field is to be as comprehensive as possible, including grey literature (Arksey & O’Malley, 2005). Inclusion and exclusion criteria must be established to help researchers eliminate studies that are not aligned with the research questions. It is also recommended that at least two independent coders review abstracts yielded from the search strategy and then the full articles for study selection ( Daudt et al., 2013 ). The synthesized evidence from content or thematic analysis is relatively easy to present in tabular form (Arksey & O’Malley, 2005; Thomas & Harden, 2008 ).

One of the most highly cited scoping reviews in the eHealth domain was published by Archer, Fevrier-Thomas, Lokker, McKibbon, and Straus (2011) . These authors reviewed the existing literature on personal health record ( phr ) systems including design, functionality, implementation, applications, outcomes, and benefits. Seven databases were searched from 1985 to March 2010. Several search terms relating to phr s were used during this process. Two authors independently screened titles and abstracts to determine inclusion status. A second screen of full-text articles, again by two independent members of the research team, ensured that the studies described phr s. All in all, 130 articles met the criteria and their data were extracted manually into a database. The authors concluded that although there is a large amount of survey, observational, cohort/panel, and anecdotal evidence of phr benefits and satisfaction for patients, more research is needed to evaluate the results of phr implementations. Their in-depth analysis of the literature signalled that there is little solid evidence from randomized controlled trials or other studies through the use of phr s. Hence, they suggested that more research is needed that addresses the current lack of understanding of optimal functionality and usability of these systems, and how they can play a beneficial role in supporting patient self-management ( Archer et al., 2011 ).

9.3.4. Forms of Aggregative Reviews

Healthcare providers, practitioners, and policy-makers are nowadays overwhelmed with large volumes of information, including research-based evidence from numerous clinical trials and evaluation studies, assessing the effectiveness of health information technologies and interventions ( Ammenwerth & de Keizer, 2004 ; Deshazo et al., 2009 ). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.

Systematic reviews attempt to aggregate, appraise, and synthesize in a single source all empirical evidence that meet a set of previously specified eligibility criteria in order to answer a clearly formulated and often narrow research question on a particular topic of interest to support evidence-based practice ( Liberati et al., 2009 ). They adhere closely to explicit scientific principles ( Liberati et al., 2009 ) and rigorous methodological guidelines (Higgins & Green, 2008) aimed at reducing random and systematic errors that can lead to deviations from the truth in results or inferences. The use of explicit methods allows systematic reviews to aggregate a large body of research evidence, assess whether effects or relationships are in the same direction and of the same general magnitude, explain possible inconsistencies between study results, and determine the strength of the overall evidence for every outcome of interest based on the quality of included studies and the general consistency among them ( Cook, Mulrow, & Haynes, 1997 ). The main procedures of a systematic review involve:

• Formulating a review question and developing a search strategy based on explicit inclusion criteria for the identification of eligible studies (usually described in the context of a detailed review protocol).
• Searching for eligible studies using multiple databases and information sources, including grey literature sources, without any language restrictions.
• Selecting studies, extracting data, and assessing risk of bias in a duplicate manner using two independent reviewers to avoid random or systematic errors in the process.
• Analyzing data using quantitative or qualitative methods.
• Presenting results in summary of findings tables.
• Interpreting results and drawing conclusions.

Many systematic reviews, but not all, use statistical methods to combine the results of independent studies into a single quantitative estimate or summary effect size. Known as meta-analyses , these reviews use specific data extraction and statistical techniques (e.g., network, frequentist, or Bayesian meta-analyses) to calculate from each study by outcome of interest an effect size along with a confidence interval that reflects the degree of uncertainty behind the point estimate of effect ( Borenstein, Hedges, Higgins, & Rothstein, 2009 ; Deeks, Higgins, & Altman, 2008 ). Subsequently, they use fixed or random-effects analysis models to combine the results of the included studies, assess statistical heterogeneity, and calculate a weighted average of the effect estimates from the different studies, taking into account their sample sizes. The summary effect size is a value that reflects the average magnitude of the intervention effect for a particular outcome of interest or, more generally, the strength of a relationship between two variables across all studies included in the systematic review. By statistically combining data from multiple studies, meta-analyses can create more precise and reliable estimates of intervention effects than those derived from individual studies alone, when these are examined independently as discrete sources of information.

The review by Gurol-Urganci, de Jongh, Vodopivec-Jamsek, Atun, and Car (2013) on the effects of mobile phone messaging reminders for attendance at healthcare appointments is an illustrative example of a high-quality systematic review with meta-analysis. Missed appointments are a major cause of inefficiency in healthcare delivery with substantial monetary costs to health systems. These authors sought to assess whether mobile phone-based appointment reminders delivered through Short Message Service ( sms ) or Multimedia Messaging Service ( mms ) are effective in improving rates of patient attendance and reducing overall costs. To this end, they conducted a comprehensive search on multiple databases using highly sensitive search strategies without language or publication-type restrictions to identify all rct s that are eligible for inclusion. In order to minimize the risk of omitting eligible studies not captured by the original search, they supplemented all electronic searches with manual screening of trial registers and references contained in the included studies. Study selection, data extraction, and risk of bias assessments were performed inde­­pen­dently by two coders using standardized methods to ensure consistency and to eliminate potential errors. Findings from eight rct s involving 6,615 participants were pooled into meta-analyses to calculate the magnitude of effects that mobile text message reminders have on the rate of attendance at healthcare appointments compared to no reminders and phone call reminders.

Meta-analyses are regarded as powerful tools for deriving meaningful conclusions. However, there are situations in which it is neither reasonable nor appropriate to pool studies together using meta-analytic methods simply because there is extensive clinical heterogeneity between the included studies or variation in measurement tools, comparisons, or outcomes of interest. In these cases, systematic reviews can use qualitative synthesis methods such as vote counting, content analysis, classification schemes and tabulations, as an alternative approach to narratively synthesize the results of the independent studies included in the review. This form of review is known as qualitative systematic review.

A rigorous example of one such review in the eHealth domain is presented by Mickan, Atherton, Roberts, Heneghan, and Tilson (2014) on the use of handheld computers by healthcare professionals and their impact on access to information and clinical decision-making. In line with the methodological guide­lines for systematic reviews, these authors: (a) developed and registered with prospero ( www.crd.york.ac.uk/ prospero / ) an a priori review protocol; (b) conducted comprehensive searches for eligible studies using multiple databases and other supplementary strategies (e.g., forward searches); and (c) subsequently carried out study selection, data extraction, and risk of bias assessments in a duplicate manner to eliminate potential errors in the review process. Heterogeneity between the included studies in terms of reported outcomes and measures precluded the use of meta-analytic methods. To this end, the authors resorted to using narrative analysis and synthesis to describe the effectiveness of handheld computers on accessing information for clinical knowledge, adherence to safety and clinical quality guidelines, and diagnostic decision-making.

In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence ( Moher, 2013 ). Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence. Umbrella reviews , also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses ( Becker & Oxman, 2008 ). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study ( Becker & Oxman, 2008 ). Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions ( Smith, Devane, Begley, & Clarke, 2011 ). A recent umbrella review on the effects of home telemonitoring interventions for patients with heart failure critically appraised, compared, and synthesized evidence from 15 systematic reviews to investigate which types of home telemonitoring technologies and forms of interventions are more effective in reducing mortality and hospital admissions ( Kitsiou, Paré, & Jaana, 2015 ).

9.3.5. Realist Reviews

Realist reviews are theory-driven interpretative reviews developed to inform, enhance, or supplement conventional systematic reviews by making sense of heterogeneous evidence about complex interventions applied in diverse contexts in a way that informs policy decision-making ( Greenhalgh, Wong, Westhorp, & Pawson, 2011 ). They originated from criticisms of positivist systematic reviews which centre on their “simplistic” underlying assumptions ( Oates, 2011 ). As explained above, systematic reviews seek to identify causation. Such logic is appropriate for fields like medicine and education where findings of randomized controlled trials can be aggregated to see whether a new treatment or intervention does improve outcomes. However, many argue that it is not possible to establish such direct causal links between interventions and outcomes in fields such as social policy, management, and information systems where for any intervention there is unlikely to be a regular or consistent outcome ( Oates, 2011 ; Pawson, 2006 ; Rousseau, Manning, & Denyer, 2008 ).

To circumvent these limitations, Pawson, Greenhalgh, Harvey, and Walshe (2005) have proposed a new approach for synthesizing knowledge that seeks to unpack the mechanism of how “complex interventions” work in particular contexts. The basic research question — what works? — which is usually associated with systematic reviews changes to: what is it about this intervention that works, for whom, in what circumstances, in what respects and why? Realist reviews have no particular preference for either quantitative or qualitative evidence. As a theory-building approach, a realist review usually starts by articulating likely underlying mechanisms and then scrutinizes available evidence to find out whether and where these mechanisms are applicable ( Shepperd et al., 2009 ). Primary studies found in the extant literature are viewed as case studies which can test and modify the initial theories ( Rousseau et al., 2008 ).

The main objective pursued in the realist review conducted by Otte-Trojel, de Bont, Rundall, and van de Klundert (2014) was to examine how patient portals contribute to health service delivery and patient outcomes. The specific goals were to investigate how outcomes are produced and, most importantly, how variations in outcomes can be explained. The research team started with an exploratory review of background documents and research studies to identify ways in which patient portals may contribute to health service delivery and patient outcomes. The authors identified six main ways which represent “educated guesses” to be tested against the data in the evaluation studies. These studies were identified through a formal and systematic search in four databases between 2003 and 2013. Two members of the research team selected the articles using a pre-established list of inclusion and exclusion criteria and following a two-step procedure. The authors then extracted data from the selected articles and created several tables, one for each outcome category. They organized information to bring forward those mechanisms where patient portals contribute to outcomes and the variation in outcomes across different contexts.

9.3.6. Critical Reviews

Lastly, critical reviews aim to provide a critical evaluation and interpretive analysis of existing literature on a particular topic of interest to reveal strengths, weaknesses, contradictions, controversies, inconsistencies, and/or other important issues with respect to theories, hypotheses, research methods or results ( Baumeister & Leary, 1997 ; Kirkevold, 1997 ). Unlike other review types, critical reviews attempt to take a reflective account of the research that has been done in a particular area of interest, and assess its credibility by using appraisal instruments or critical interpretive methods. In this way, critical reviews attempt to constructively inform other scholars about the weaknesses of prior research and strengthen knowledge development by giving focus and direction to studies for further improvement ( Kirkevold, 1997 ).

Kitsiou, Paré, and Jaana (2013) provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes. To this end, they provide a number of recommendations to strengthen knowledge development towards improving the design and execution of future reviews on home telemonitoring.

9.4. Summary

Table 9.1 outlines the main types of literature reviews that were described in the previous sub-sections and summarizes the main characteristics that distinguish one review type from another. It also includes key references to methodological guidelines and useful sources that can be used by eHealth scholars and researchers for planning and developing reviews.

Typology of Literature Reviews (adapted from Paré et al., 2015).

As shown in Table 9.1 , each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal(s) of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles ( Green et al., 2006 ). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions. On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an “a priori” review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Some reviews are exploratory in nature (e.g., scoping/mapping reviews), whereas others may be conducted to discover patterns (e.g., descriptive reviews) or involve a synthesis approach that may include the critical analysis of prior research ( Paré et al., 2015 ). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals.

9.5. Concluding Remarks

In light of the increased use of evidence-based practice and research generating stronger evidence ( Grady et al., 2011 ; Lyden et al., 2013 ), review articles have become essential tools for summarizing, synthesizing, integrating or critically appraising prior knowledge in the eHealth field. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.

We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another ( Paré et al., 2015 ). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review. Whether the search is comprehensive or not, whether it involves a methodical approach for data extraction and synthesis or not, it is important that the review documents in an explicit and transparent manner the steps and approach that were used in the process of its development. Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches ( vom Brocke et al., 2009 ). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used. We refer those interested in the concepts of rigour and quality to the work of Templier and Paré (2015) which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles.

To conclude, our main objective in this chapter was to demystify the various types of literature reviews that are central to the continuous development of the eHealth field. It is our hope that our descriptive account will serve as a valuable source for those conducting, evaluating or using reviews in this important and growing domain.

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• Overview of the Literature Review Process and Steps
• Types of Review Articles and Brief Illustrations
• Concluding Remarks

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What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Discovers relationships between research studies/ideas.
• Identifies major themes, concepts, and researchers on a topic.
• Identifies critical gaps and points of disagreement.
• Discusses further research questions that logically come out of the previous studies.

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1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

• Make sure your research question is not too broad or too narrow.  Is it manageable?
• Begin writing down terms that are related to your question. These will be useful for searches later.
• If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

• use the tabs on this guide
• Find other databases in the Nursing Information Resources web page
• More on the Medical Library web page
• ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

• Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
• Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
• Review the abstracts of research studies carefully. This will save you time.
• Use the bibliographies and references of research studies you find to locate others.
• Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
• Ask your librarian for help at any time.
• Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

• What was the research question of the study you are reviewing? What were the authors trying to discover?
• Was the research funded by a source that could influence the findings?
• What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
• Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
• If there are conflicting studies, why do you think that is?
• How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

• Review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
• Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
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The Literature Review

28 The Literature Review

A literature review is a survey of everything that has been written about a particular topic, theory, or research question. The word “literature” means “sources of information”. The literature will inform you about the research that has already been conducted on your chosen subject. This is important because we do not want to repeat research that has already been done unless there is a good reason for doing so (i.e. there has been a new development in this area or testing a theory with a new population, or even just to see if the research can be reproduced).  Literature reviews usually serve as a background for a larger work (e.g. as part of a research proposal), or it may stand on its own. Much more than a simple list of sources, an effective literature review analyzes and synthesizes information about key themes or issues.

Purpose of a literature review

The literature review involves an extensive study of research publications, books and other documents related to the defined problem.  The study is important because it advises you, as a researcher, whether the problem you identified has already been solved by other researchers.  It also advises you as to the status of the problem, techniques that have been used by other researchers to investigate the problem, and other related details.

A literature review goes beyond the search for information and includes the identification and articulation of relationships between existing literature and your field of research. The literature review enables the researcher to discover what has been already been written about a topic and to understand the relationship between the various contributions. This will enable the researcher to determine the contributions of each sources (books, article, etc.) to the topic. Literature reviews also enable the researcher to identify and (if possible) resolve contradictions, and also determine research gaps and/or unanswered questions.

Even though the nature of the literature review may vary with different types of studies, the basic purposes remain constant and could be summarized as follows:

• Provide a context for your research;
• Justify the research you are proposing;
• Ensure that your proposed research has not been carried out by another person (and if you find it has, then your literature review should specify why replication is necessary);
• Show where your proposed research fits into the existing body of knowledge;
• Enable the researcher to learn from previous theory on the subject;
• Illustrate how the subject has been studied previously;
• Highlight flaws in previous research;
• Outline gaps in previous research;
• Show how your proposed research can add to the understanding and knowledge of the field;
• Help refine, refocus, or even move the topic in a new direction

What is involved in writing a literature review?

• Research – to discover what has been written about the topic;
• Critical Appraisal – to evaluate the literature, determine the relationship between the sources and ascertain what has been done already and what still needs to be done;
• Writing – to explain what you have found

Generally speaking, it is helpful to think of the literature review as a funnel.  One starts with a broad examination of the research related to the issue, working down to look at more specific aspects of the issue, which leads to the gap or the specific issue that your research will address.

How to undertake a literature review

The first step in undertaking a literature review is to conduct a library search of academic research that has been done on your topic.  This can be done electronically, or if you are within close vicinity to a library, you can go in and use their computers to find electronic and print holdings. You can also use Google Scholar for your search.  In some cases, research conducted outside academia can serve as an important research source for your literature review. Indeed, such research can have important practical implications, as opposed to academic research which usually (although not always) tends toward theoretical applications.

However, it is important to understand who funded the research you review, in addition to the perspective and the purpose of the research.  This is becoming an issue in Canada as universities and colleges increasingly turn to industry for research funding grants (see How TransAlta used a university-sanctioned research project to lobby for the coal industry ).

As part of this first step there are a few more some things to be thinking about as you review the literature, as follows:

• Who are the various researchers who have studied this topic?  Who are the most prolific researchers/writers on this topic? Has a specific researcher or teams of researchers been identified as pioneers or leaders in this field of study?
• How have the various researchers defined key terms that are relevant to your topic? Have the definitions of any of the key terms evolved over time?
• What are the different theories that have been examined and applied to this topic? How, if at all, have the various theories applied to this topic over time evolved?
• What methodologies have been used to study this topic?  Have the methodologies evolved over time?

In addition to thinking about these questions, you should be taking notes during this process. It can be helpful to keep these notes in an Excel file.  For example, your notes should include the following information:

• If the article is empirical, write down the results of the research study in one or two sentences of your own words. e.g. “people who are between ages 18 – 35 are more likely to own a smart phone than those above or below.”  It is also a good idea to make note of the methods, the research design, the number of participants and details on the sample used in the study. Sometimes, you may even want to write down the names of the statistical procedures used to analyze the data or even some of the statistics, depending on your assignment.
• If the article is a review of previous research, look for the main points. It may be helpful to read or skim the whole article, look away, and ask yourself what you felt was the main idea.
• Write down any limitations or gaps you notice, anything that seems to contradict something you read elsewhere, or just anything that you think is important or interesting (Adjei, n.d.)

When reading through your sources, remember that you are looking for the “big picture,” not a collection of random, separate articles (an annotated bibliography).  You are also not trying to prove a point (an essay). You are looking for common themes and patterns in the research as a whole. You are also looking to see how the various pieces of research are linked, if at all.  As part of this process, you also want to identify research gaps or areas that require further research related your topic (Adjei, n.d.). In this regard, you cannot be expected to be an expert on your topic. A suggestion for finding gaps is to read the conclusion section of the academic journal articles and conference proceedings your search has uncovered.  Researchers often identify gaps in the research in their conclusion. They may even suggest areas for future research. However, remember, if a researcher suggested a gap 10 years ago, it is likely that the gap has now been addressed. To find a gap, look at the most recent research your literature review has uncovered (within 2-3 years of the current date). At this point in your search of the literature, you may realize that your research question needs to change or adapt.  This is a fairly common occurrence, as when you first develop a research question, you cannot be sure what the status of the research area is, until you undertake your review of the literature related to this topic. Finally, it is worth mentioning that it is very likely you will not include all of the resources you have read in your literature review. If you are asked to include 20 resources in your literature review, for example, expect to read approximately 30.

How to write a literature review

There are three parts to the literature review: the introduction, the body, and the conclusion.  In the following paragraphs we outline what to include in each of these sections. This section concludes with a variety of resources for you to check out.

Introduction

• The introduction must identify the topic by briefly discussing the significance of the topic including a statement that outlines the conclusion to be drawn from the literature review.
• If your literature review is part of a larger work, explain the importance of the review to your research question.
• Defend the importance of the topic by giving a broad overview of the scope of the work you are reviewing. For example, if you are interested in post traumatic stress disorder (PTSD) in paramedics, you might provide some stats to prove how much work time is lost by those suffering from PTSD.
• Clarify whether you are looking at the entire history of the field, or just a particular period of time.
• Discuss and assess the research according to specific organizational principles (see examples below), rather than addressing each source separately. Most, if not all, paragraphs should discuss more than one source. Avoid addressing your sources alphabetically as this does not assist in developing the themes or key issues central to your review.
• Compare, contrast, and connect the various pieces of research. Much of the research you are reading should be connected.  Or you may notice various themes within the research (i.e. effects of PTSD on sick time, effects of PTSD on families of paramedics, effects of PTSD on overall paramedic wellness, etc.).  If you have undertaken a thorough review of the literature, you should start to see the bigger picture of how the research on this topic has evolved over time, who the main researchers are on this topic, how the methods and theories related to this topic have changed (if at all), over time.
• Summarize the works you are reviewing. Just as in any written assignment, use logical organization and clear transitions. Spend more time on the researchers and bodies of research that are considered most important in the field and/or that are most relevant.

Based upon your research, suggest where the research in the field will or should go next. If you are proposing your own research study, show how you will contribute to the field and fill in any gaps. The conclusion would also be a good place to defend the importance of the topic, now that you have demonstrated the current state of thinking in the field.

Other resources to help you write a literature review

In conclusion, there is a plethora of resources, both here and online, that provide information on how to write a literature review. For example, check out these three, very helpful YouTube videos prepared by a professor at the University of Maryland, in the U.S.A:

• The Literature Review, Part 1
• The Literature Review, Part 2
• The Literature Review, Part 3

Table 5.1 also provides some suggested organizational techniques, as well as instances when you might use these various techniques.  The table also provides a writing sample to demonstrate the writing technique.

And remember, most university and college libraries also have valuable information on literature reviews.  Here is the link to one such website: JIBC Literature Review information [PDF]

Acceptable sources for literature reviews

There are a few acceptable sources for literature reviews, and I will list these in order from what will be considered most acceptable to less acceptable sources for your literature review assignments, as follows:

• Peer reviewed journal articles;
• Edited academic books;
• Articles in professional journals;
• Statistical data from government websites;
• Website material from professional associations (use sparingly and carefully);

The following sections will explain and provide examples of these various sources.

Peer reviewed journal articles (papers)

A peer reviewed journal article is a paper that has been submitted to a scholarly journal, accepted, and published.  Peer review journal papers go through a rigorous, blind review process of peer review. What this means is that two to three experts in the area of research featured in the paper have reviewed and accepted the paper for publication. The names of the author(s) who are seeking to publish the research have been removed (blind review), so as to minimize any bias towards the authors of the research. Albeit, sometimes a savvy reviewer can discern who has done the research based upon previous publications, etc.  This blind review process can be long (often 12 to 18 months) that may involve many back and forth edits on the behalf of the researchers, as they work to address the edits and concerns of the peers who reviewed their paper. Often, reviewers will reject the paper for a variety of reasons, such as unclear or questionable methods, lack of contribution to the field, etc. Because peer reviewed journal articles have gone through a rigorous process of review, they are considered to be the premier source for research. Peer reviewed journal articles should serve as the foundation for your literature review.

The following website will provide more information on peer-reviewed journal articles: Evaluating Information Sources: What Is A Peer-Reviewed Article? Make sure you watch the little video on the upper left-hand side of your screen, in addition to reading the material.

Edited academic books

An edited academic book is a collection of scholarly scientific papers written by different authors. The works are original papers, not published elsewhere (Wikipedia, 2018).  The papers within the text also go through a process of review; however, the review is often not a blind review because the authors have been invited to contribute to the book. Consequently, edited academic books are fine to use for your literature review, but you also want to ensure that your literature review contains mostly peer reviewed journal papers.

Articles in professional journals.

Articles from professional journals should be used with caution, as far as it relates to a source for your literature review.  This is because articles in trade journals are not usually peer reviewed, even though they may appear as such. A good way to find out is to read the “About us” section of the professional journal.  They should state there if the papers are peer reviewed. You can also google the name of the journal and add peer reviewed to the search and you should be able to find out that way.

Statistical data from governmental websites.

Governmental websites can be excellent sources for statistical data.  For examples, Statistics Canada collects and publishes data related to the economy, society, and the environment.

Website material from professional associations

Material from other websites can also serve as a source for statistics that you may need for your literature review.  As you want to justify the value of the research you are interested in, you might make use of a professional association´s website to learn how many members they have, for example.  As a hypothetical example, you might want to demonstrate, as part of the introduction to your literature review, why more research on the topic of PTSD in police officers is important.  You could use peer reviewed journal articles to determine the prevalence of PTSD in police officers in Canada in the last ten years and then use the Ontario Police Officers´ Association website to determine the approximate number of police officers employed in the Province of Ontario over the last ten years. This might help you create an approximation of how many police officers could be suffering with PTSD in Ontario.  That number could potentially help to justify a research grand down the road. But again, this type of website-based material should be used with caution and sparingly.

Text Attributions

• This chapter has been adapted from Unit 2: Literature Review in  Research Methods by  Joseph K. Adjei. © Creative Commons Attribution-ShareAlike 3.0 License .

The Literature Review Copyright © 2019 by Valerie A. Sheppard is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License , except where otherwise noted.

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State-of-the-art literature review methodology: A six-step approach for knowledge synthesis

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Introduction

Researchers and practitioners rely on literature reviews to synthesize large bodies of knowledge. Many types of literature reviews have been developed, each targeting a specific purpose. However, these syntheses are hampered if the review type’s paradigmatic roots, methods, and markers of rigor are only vaguely understood. One literature review type whose methodology has yet to be elucidated is the state-of-the-art (SotA) review. If medical educators are to harness SotA reviews to generate knowledge syntheses, we must understand and articulate the paradigmatic roots of, and methods for, conducting SotA reviews.

We reviewed 940 articles published between 2014–2021 labeled as SotA reviews. We (a) identified all SotA methods-related resources, (b) examined the foundational principles and techniques underpinning the reviews, and (c) combined our findings to inductively analyze and articulate the philosophical foundations, process steps, and markers of rigor.

In the 940 articles reviewed, nearly all manuscripts (98%) lacked citations for how to conduct a SotA review. The term “state of the art” was used in 4 different ways. Analysis revealed that SotA articles are grounded in relativism and subjectivism.

This article provides a 6-step approach for conducting SotA reviews. SotA reviews offer an interpretive synthesis that describes: This is where we are now. This is how we got here. This is where we could be going. This chronologically rooted narrative synthesis provides a methodology for reviewing large bodies of literature to explore why and how our current knowledge has developed and to offer new research directions.

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Literature reviews play a foundational role in scientific research; they support knowledge advancement by collecting, describing, analyzing, and integrating large bodies of information and data [ 1 , 2 ]. Indeed, as Snyder [ 3 ] argues, all scientific disciplines require literature reviews grounded in a methodology that is accurate and clearly reported. Many types of literature reviews have been developed, each with a unique purpose, distinct methods, and distinguishing characteristics of quality and rigor [ 4 , 5 ].

Each review type offers valuable insights if rigorously conducted [ 3 , 6 ]. Problematically, this is not consistently the case, and the consequences can be dire. Medical education’s policy makers and institutional leaders rely on knowledge syntheses to inform decision making [ 7 ]. Medical education curricula are shaped by these syntheses. Our accreditation standards are informed by these integrations. Our patient care is guided by these knowledge consolidations [ 8 ]. Clearly, it is important for knowledge syntheses to be held to the highest standards of rigor. And yet, that standard is not always maintained. Sometimes scholars fail to meet the review’s specified standards of rigor; other times the markers of rigor have never been explicitly articulated. While we can do little about the former, we can address the latter. One popular literature review type whose methodology has yet to be fully described, vetted, and justified is the state-of-the-art (SotA) review.

While many types of literature reviews amalgamate bodies of literature, SotA reviews offer something unique. By looking across the historical development of a body of knowledge, SotA reviews delves into questions like: Why did our knowledge evolve in this way? What other directions might our investigations have taken? What turning points in our thinking should we revisit to gain new insights? A SotA review—a form of narrative knowledge synthesis [ 5 , 9 ]—acknowledges that history reflects a series of decisions and then asks what different decisions might have been made.

SotA reviews are frequently used in many fields including the biomedical sciences [ 10 , 11 ], medicine [ 12 , 13 , 14 ], and engineering [ 15 , 16 ]. However, SotA reviews are rarely seen in medical education; indeed, a bibliometrics analysis of literature reviews published in 14 core medical education journals between 1999 and 2019 reported only 5 SotA reviews out of the 963 knowledge syntheses identified [ 17 ]. This is not to say that SotA reviews are absent; we suggest that they are often unlabeled. For instance, Schuwirth and van der Vleuten’s article “A history of assessment in medical education” [ 14 ] offers a temporally organized overview of the field’s evolving thinking about assessment. Similarly, McGaghie et al. published a chronologically structured review of simulation-based medical education research that “reviews and critically evaluates historical and contemporary research on simulation-based medical education” [ 18 , p. 50]. SotA reviews certainly have a place in medical education, even if that place is not explicitly signaled.

This lack of labeling is problematic since it conceals the purpose of, and work involved in, the SotA review synthesis. In a SotA review, the author(s) collects and analyzes the historical development of a field’s knowledge about a phenomenon, deconstructs how that understanding evolved, questions why it unfolded in specific ways, and posits new directions for research. Senior medical education scholars use SotA reviews to share their insights based on decades of work on a topic [ 14 , 18 ]; their junior counterparts use them to critique that history and propose new directions [ 19 ]. And yet, SotA reviews are generally not explicitly signaled in medical education. We suggest that at least two factors contribute to this problem. First, it may be that medical education scholars have yet to fully grasp the unique contributions SotA reviews provide. Second, the methodology and methods of SotA reviews are poorly reported making this form of knowledge synthesis appear to lack rigor. Both factors are rooted in the same foundational problem: insufficient clarity about SotA reviews. In this study, we describe SotA review methodology so that medical educators can explicitly use this form of knowledge synthesis to further advance the field.

We developed a four-step research design to meet this goal, illustrated in Fig.  1 .

Four-step research design process used for developing a State-of-the-Art literature review methodology

Step 1: Collect SotA articles

To build our initial corpus of articles reporting SotA reviews, we searched PubMed using the strategy (″state of the art review″[ti] OR ″state of the art review*″) and limiting our search to English articles published between 2014 and 2021. We strategically focused on PubMed, which includes MEDLINE, and is considered the National Library of Medicine’s premier database of biomedical literature and indexes health professions education and practice literature [ 20 ]. We limited our search to 2014–2021 to capture modern use of SotA reviews. Of the 960 articles identified, nine were excluded because they were duplicates, erratum, or corrigendum records; full text copies were unavailable for 11 records. All articles identified ( n  = 940) constituted the corpus for analysis.

Step 2: Compile all methods-related resources

EB, JM, or LV independently reviewed the 940 full-text articles to identify all references to resources that explained, informed, described, or otherwise supported the methods used for conducting the SotA review. Articles that met our criteria were obtained for analysis.

To ensure comprehensive retrieval, we also searched Scopus and Web of Science. Additionally, to find resources not indexed by these academic databases, we searched Google (see Electronic Supplementary Material [ESM] for the search strategies used for each database). EB also reviewed the first 50 items retrieved from each search looking for additional relevant resources. None were identified. Via these strategies, nine articles were identified and added to the collection of methods-related resources for analysis.

Step 3: Extract data for analysis

In Step 3, we extracted three kinds of information from the 940 articles papers identified in Step 1. First, descriptive data on each article were compiled (i.e., year of publication and the academic domain targeted by the journal). Second, each article was examined and excerpts collected about how the term state-of-the-art review was used (i.e., as a label for a methodology in-and-of itself; as an adjective qualifying another type of literature review; as a term included in the paper’s title only; or in some other way). Finally, we extracted excerpts describing: the purposes and/or aims of the SotA review; the methodology informing and methods processes used to carry out the SotA review; outcomes of analyses; and markers of rigor for the SotA review.

Two researchers (EB and JM) coded 69 articles and an interrater reliability of 94.2% was achieved. Any discrepancies were discussed. Given the high interrater reliability, the two authors split the remaining articles and coded independently.

Step 4: Construct the SotA review methodology

The methods-related resources identified in Step 2 and the data extractions from Step 3 were inductively analyzed by LV and EB to identify statements and research processes that revealed the ontology (i.e., the nature of reality that was reflected) and the epistemology (i.e., the nature of knowledge) underpinning the descriptions of the reviews. These authors studied these data to determine if the synthesis adhered to an objectivist or a subjectivist orientation, and to synthesize the purposes realized in these papers.

To confirm these interpretations, LV and EB compared their ontology, epistemology, and purpose determinations against two expectations commonly required of objectivist synthesis methods (e.g., systematic reviews): an exhaustive search strategy and an appraisal of the quality of the research data. These expectations were considered indicators of a realist ontology and objectivist epistemology [ 21 ] (i.e., that a single correct understanding of the topic can be sought through objective data collection {e.g., systematic reviews [ 22 ]}). Conversely, the inverse of these expectations were considered indicators of a relativist ontology and subjectivist epistemology [ 21 ] (i.e., that no single correct understanding of the topic is available; there are multiple valid understandings that can be generated and so a subjective interpretation of the literature is sought {e.g., narrative reviews [ 9 ]}).

Once these interpretations were confirmed, LV and EB reviewed and consolidated the methods steps described in these data. Markers of rigor were then developed that aligned with the ontology, epistemology, and methods of SotA reviews.

Of the 940 articles identified in Step 1, 98% ( n  = 923) lacked citations or other references to resources that explained, informed, or otherwise supported the SotA review process. Of the 17 articles that included supporting information, 16 cited Grant and Booth’s description [ 4 ] consisting of five sentences describing the overall purpose of SotA reviews, three sentences noting perceived strengths, and four sentences articulating perceived weaknesses. This resource provides no guidance on how to conduct a SotA review methodology nor markers of rigor. The one article not referencing Grant and Booth used “an adapted comparative effectiveness research search strategy that was adapted by a health sciences librarian” [ 23 , p. 381]. One website citation was listed in support of this strategy; however, the page was no longer available in summer 2021. We determined that the corpus was uninformed by a cardinal resource or a publicly available methodology description.

In Step 2 we identified nine resources [ 4 , 5 , 24 , 25 , 26 , 27 , 28 ]; none described the methodology and/or processes of carrying out SotA reviews. Nor did they offer explicit descriptions of the ontology or epistemology underpinning SotA reviews. Instead, these resources provided short overview statements (none longer than one paragraph) about the review type [ 4 , 5 , 24 , 25 , 26 , 27 , 28 ]. Thus, we determined that, to date, there are no available methodology papers describing how to conduct a SotA review.

Step 3 revealed that “state of the art” was used in 4 different ways across the 940 articles (see Fig.  2 for the frequency with which each was used). In 71% ( n  = 665 articles), the phrase was used only in the title, abstract, and/or purpose statement of the article; the phrase did not appear elsewhere in the paper and no SotA methodology was discussed. Nine percent ( n  = 84) used the phrase as an adjective to qualify another literature review type and so relied entirely on the methodology of a different knowledge synthesis approach (e.g., “a state of the art systematic review [ 29 ]”). In 5% ( n  = 52) of the articles, the phrase was not used anywhere within the article; instead, “state of the art” was the type of article within a journal. In the remaining 15% ( n  = 139), the phrase denoted a specific methodology (see ESM for all methodology articles). Via Step 4’s inductive analysis, the following foundational principles of SotA reviews were developed: (1) the ontology, (2) epistemology, and (3) purpose of SotA reviews.

Four ways the term “state of the art” is used in the corpus and how frequently each is used

Ontology of SotA reviews: Relativism

SotA reviews rest on four propositions:

The literature addressing a phenomenon offers multiple perspectives on that topic (i.e., different groups of researchers may hold differing opinions and/or interpretations of data about a phenomenon).

The reality of the phenomenon itself cannot be completely perceived or understood (i.e., due to limitations [e.g., the capabilities of current technologies, a research team’s disciplinary orientation] we can only perceive a limited part of the phenomenon).

The reality of the phenomenon is a subjective and inter-subjective construction (i.e., what we understand about a phenomenon is built by individuals and so their individual subjectivities shape that understanding).

The context in which the review was conducted informs the review (e.g., a SotA review of literature about gender identity and sexual function will be synthesized differently by researchers in the domain of gender studies than by scholars working in sex reassignment surgery).

As these propositions suggest, SotA scholars bring their experiences, expectations, research purposes, and social (including academic) orientations to bear on the synthesis work. In other words, a SotA review synthesizes the literature based on a specific orientation to the topic being addressed. For instance, a SotA review written by senior scholars who are experts in the field of medical education may reflect on the turning points that have shaped the way our field has evolved the modern practices of learner assessment, noting how the nature of the problem of assessment has moved: it was first a measurement problem, then a problem that embraced human judgment but needed assessment expertise, and now a whole system problem that is to be addressed from an integrated—not a reductionist—perspective [ 12 ]. However, if other scholars were to examine this same history from a technological orientation, learner assessment could be framed as historically constricted by the media available through which to conduct assessment, pointing to how artificial intelligence is laying the foundation for the next wave of assessment in medical education [ 30 ].

Given these foundational propositions, SotA reviews are steeped in a relativist ontology—i.e., reality is socially and experientially informed and constructed, and so no single objective truth exists. Researchers’ interpretations reflect their conceptualization of the literature—a conceptualization that could change over time and that could conflict with the understandings of others.

Epistemology of SotA reviews: Subjectivism

SotA reviews embrace subjectivism. The knowledge generated through the review is value-dependent, growing out of the subjective interpretations of the researcher(s) who conducted the synthesis. The SotA review generates an interpretation of the data that is informed by the expertise, experiences, and social contexts of the researcher(s). Furthermore, the knowledge developed through SotA reviews is shaped by the historical point in time when the review was conducted. SotA reviews are thus steeped in the perspective that knowledge is shaped by individuals and their community, and is a synthesis that will change over time.

Purpose of SotA reviews

SotA reviews create a subjectively informed summary of modern thinking about a topic. As a chronologically ordered synthesis, SotA reviews describe the history of turning points in researchers’ understanding of a phenomenon to contextualize a description of modern scientific thinking on the topic. The review presents an argument about how the literature could be interpreted; it is not a definitive statement about how the literature should or must be interpreted. A SotA review explores: the pivotal points shaping the historical development of a topic, the factors that informed those changes in understanding, and the ways of thinking about and studying the topic that could inform the generation of further insights. In other words, the purpose of SotA reviews is to create a three-part argument: This is where we are now in our understanding of this topic. This is how we got here. This is where we could go next.

The SotA methodology

Based on study findings and analyses, we constructed a six-stage SotA review methodology. This six-stage approach is summarized and guiding questions are offered in Tab.  1 .

Stage 1: Determine initial research question and field of inquiry

In Stage 1, the researcher(s) creates an initial description of the topic to be summarized and so must determine what field of knowledge (and/or practice) the search will address. Knowledge developed through the SotA review process is shaped by the context informing it; thus, knowing the domain in which the review will be conducted is part of the review’s foundational work.

Stage 2: Determine timeframe

This stage involves determining the period of time that will be defined as SotA for the topic being summarized. The researcher(s) should engage in a broad-scope overview of the literature, reading across the range of literature available to develop insights into the historical development of knowledge on the topic, including the turning points that shape the current ways of thinking about a topic. Understanding the full body of literature is required to decide the dates or events that demarcate the timeframe of now in the first of the SotA’s three-part argument: where we are now . Stage 2 is complete when the researcher(s) can explicitly justify why a specific year or event is the right moment to mark the beginning of state-of-the-art thinking about the topic being summarized.

Stage 3: Finalize research question(s) to reflect timeframe

Based on the insights developed in Stage 2, the researcher(s) will likely need to revise their initial description of the topic to be summarized. The formal research question(s) framing the SotA review are finalized in Stage 3. The revised description of the topic, the research question(s), and the justification for the timeline start year must be reported in the review article. These are markers of rigor and prerequisites for moving to Stage 4.

Stage 4: Develop search strategy to find relevant articles

In Stage 4, the researcher(s) develops a search strategy to identify the literature that will be included in the SotA review. The researcher(s) needs to determine which literature databases contain articles from the domain of interest. Because the review describes how we got here , the review must include literature that predates the state-of-the-art timeframe, determined in Stage 2, to offer this historical perspective.

Developing the search strategy will be an iterative process of testing and revising the search strategy to enable the researcher(s) to capture the breadth of literature required to meet the SotA review purposes. A librarian should be consulted since their expertise can expedite the search processes and ensure that relevant resources are identified. The search strategy must be reported (e.g., in the manuscript itself or in a supplemental file) so that others may replicate the process if they so choose (e.g., to construct a different SotA review [and possible different interpretations] of the same literature). This too is a marker of rigor for SotA reviews: the search strategies informing the identification of literature must be reported.

Stage 5: Analyses

The literature analysis undertaken will reflect the subjective insights of the researcher(s); however, the foundational premises of inductive research should inform the analysis process. Therefore, the researcher(s) should begin by reading the articles in the corpus to become familiar with the literature. This familiarization work includes: noting similarities across articles, observing ways-of-thinking that have shaped current understandings of the topic, remarking on assumptions underpinning changes in understandings, identifying important decision points in the evolution of understanding, and taking notice of gaps and assumptions in current knowledge.

The researcher(s) can then generate premises for the state-of-the-art understanding of the history that gave rise to modern thinking, of the current body of knowledge, and of potential future directions for research. In this stage of the analysis, the researcher(s) should document the articles that support or contradict their premises, noting any collections of authors or schools of thinking that have dominated the literature, searching for marginalized points of view, and studying the factors that contributed to the dominance of particular ways of thinking. The researcher(s) should also observe historical decision points that could be revisited. Theory can be incorporated at this stage to help shape insights and understandings. It should be highlighted that not all corpus articles will be used in the SotA review; instead, the researcher(s) will sample across the corpus to construct a timeline that represents the seminal moments of the historical development of knowledge.

Next, the researcher(s) should verify the thoroughness and strength of their interpretations. To do this, the researcher(s) can select different articles included in the corpus and examine if those articles reflect the premises the researcher(s) set out. The researcher(s) may also seek out contradictory interpretations in the literature to be sure their summary refutes these positions. The goal of this verification work is not to engage in a triangulation process to ensure objectivity; instead, this process helps the researcher(s) ensure the interpretations made in the SotA review represent the articles being synthesized and respond to the interpretations offered by others. This is another marker of rigor for SotA reviews: the authors should engage in and report how they considered and accounted for differing interpretations of the literature, and how they verified the thoroughness of their interpretations.

Stage 6: Reflexivity

Given the relativist subjectivism of a SotA review, it is important that the manuscript offer insights into the subjectivity of the researcher(s). This reflexivity description should articulate how the subjectivity of the researcher(s) informed interpretations of the data. These reflections will also influence the suggested directions offered in the last part of the SotA three-part argument: where we could go next. This is the last marker of rigor for SotA reviews: researcher reflexivity must be considered and reported.

SotA reviews have much to offer our field since they provide information on the historical progression of medical education’s understanding of a topic, the turning points that guided that understanding, and the potential next directions for future research. Those future directions may question the soundness of turning points and prior decisions, and thereby offer new paths of investigation. Since we were unable to find a description of the SotA review methodology, we inductively developed a description of the methodology—including its paradigmatic roots, the processes to be followed, and the markers of rigor—so that scholars can harness the unique affordances of this type of knowledge synthesis.

Given their chronology- and turning point-based orientation, SotA reviews are inherently different from other types of knowledge synthesis. For example, systematic reviews focus on specific research questions that are narrow in scope [ 32 , 33 ]; in contrast, SotA reviews present a broader historical overview of knowledge development and the decisions that gave rise to our modern understandings. Scoping reviews focus on mapping the present state of knowledge about a phenomenon including, for example, the data that are currently available, the nature of that data, and the gaps in knowledge [ 34 , 35 ]; conversely, SotA reviews offer interpretations of the historical progression of knowledge relating to a phenomenon centered on significant shifts that occurred during that history. SotA reviews focus on the turning points in the history of knowledge development to suggest how different decisions could give rise to new insights. Critical reviews draw on literature outside of the domain of focus to see if external literature can offer new ways of thinking about the phenomenon of interest (e.g., drawing on insights from insects’ swarm intelligence to better understand healthcare team adaptation [ 36 ]). SotA reviews focus on one domain’s body of literature to construct a timeline of knowledge development, demarcating where we are now, demonstrating how this understanding came to be via different turning points, and offering new research directions. Certainly, SotA reviews offer a unique kind of knowledge synthesis.

Our six-stage process for conducting these reviews reflects the subjectivist relativism that underpins the methodology. It aligns with the requirements proposed by others [ 24 , 25 , 26 , 27 ], what has been written about SotA reviews [ 4 , 5 ], and the current body of published SotA reviews. In contrast to existing guidance [ 4 , 5 , 20 , 21 , 22 , 23 ], our description offers a detailed reporting of the ontology, epistemology, and methodology processes for conducting the SotA review.

This explicit methodology description is essential since many academic journals list SotA reviews as an accepted type of literature review. For instance, Educational Research Review [ 24 ], the American Academy of Pediatrics [ 25 ], and Thorax all lists SotA reviews as one of the types of knowledge syntheses they accept [ 27 ]. However, while SotA reviews are valued by academia, guidelines or specific methodology descriptions for researchers to follow when conducting this type of knowledge synthesis are conspicuously absent. If academics in general, and medical education more specifically, are to take advantage of the insights that SotA reviews can offer, we need to rigorously engage in this synthesis work; to do that, we need clear descriptions of the methodology underpinning this review. This article offers such a description. We hope that more medical educators will conduct SotA reviews to generate insights that will contribute to further advancing our field’s research and scholarship.

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Acknowledgements

We thank Rhonda Allard for her help with the literature review and compiling all available articles. We also want to thank the PME editors who offered excellent development and refinement suggestions that greatly improved this manuscript.

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40037_2022_725_moesm1_esm.docx.

For information regarding the search strategy to develop the corpus and search strategy for confirming capture of any available State of the Art review methodology descriptions. Additionally, a list of the methodology articles found through the search strategy/corpus is included

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Barry, E.S., Merkebu, J. & Varpio, L. State-of-the-art literature review methodology: A six-step approach for knowledge synthesis. Perspect Med Educ 11 , 281–288 (2022). https://doi.org/10.1007/s40037-022-00725-9

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DOI : https://doi.org/10.1007/s40037-022-00725-9

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What are research methods?

Research methodology is the specific strategies, processes, or techniques utilised in the collection of information that is created and analysed.

The methodology section of a research paper, or thesis, enables the reader to critically evaluate the study’s validity and reliability by addressing how the data was collected or generated, and how it was analysed.

Types of research methods

There are three main types of research methods which use different designs for data collection.  

(1) Qualitative research

Qualitative research gathers data about lived experiences, emotions or behaviours, and the meanings individuals attach to them. It assists in enabling researchers to gain a better understanding of complex concepts, social interactions or cultural phenomena. This type of research is useful in the exploration of how or why things have occurred, interpreting events and describing actions.

Examples of qualitative research designs include:

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(2) Quantitative research

Quantitative research gathers numerical data which can be ranked, measured or categorised through statistical analysis. It assists with uncovering patterns or relationships, and for making generalisations. This type of research is useful for finding out how many, how much, how often, or to what extent.

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Mixed Methods research integrates both Qualitative research and Quantitative research. It provides a holistic approach combining and analysing the statistical data with deeper contextualised insights. Using Mixed Methods also enables triangulation, or verification, of the data from two or more sources.

Sometimes in your literature review, you might need to discuss and evaluate relevant research methodologies in order to justify your own choice of research methodology.

When searching for literature on research methodologies it is important to search across a range of sources. No single information source will supply all that you need. Selecting appropriate sources will depend upon your research topic.

Developing a robust search strategy will help reduce irrelevant results. It is good practice to plan a strategy before you start to search.

Search tips

(1) free text keywords.

Free text searching is the use of natural language words to conduct your search. Use selective free text keywords such as: phenomenological, "lived experience", "grounded theory", "life experiences", "focus groups", interview, quantitative, survey, validity, variance, correlation and statistical.

To locate books on your desired methodology, try LibrarySearch . Remember to use  refine  options such as books, ebooks, subject, and publication date.  

(2) Subject headings in Databases

Databases categorise their records using subject terms, or a controlled vocabulary (thesaurus). These subject headings may be useful to use, in addition to utilising free text keywords in a database search.

Subject headings will differ across databases, for example, the PubMed database uses 'Qualitative Research' whilst the CINHAL database uses 'Qualitative Studies.'  

(3) Limiting search results

Databases enable sets of results to be limited or filtered by specific fields, look for options such as Publication Type, Article Type, etc. and apply them to your search.  

(4) Browse the Library shelves

To find books on  research methods  browse the Library shelves at call number  001.42

• SAGE Research Methods Online SAGE Research Methods Online (SRMO) is a research tool supported by a newly devised taxonomy that links content and methods terms. It provides the most comprehensive picture available today of research methods (quantitative, qualitative and mixed methods) across the social and behavioural sciences.

SAGE Research Methods Overview  (2:07 min) by SAGE Publishing  ( YouTube ) 

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• Last Updated: Jul 31, 2024 12:02 PM
• URL: https://rmit.libguides.com/literature-review

Doing a Scoping Review: A Practical, Step-by-Step Guide

Saul Mcleod, PhD

Editor-in-Chief for Simply Psychology

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Saul Mcleod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Learn about our Editorial Process

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

On This Page:

What is a Scoping Review?

A scoping review is a type of research synthesis that maps the existing literature on a broad topic to identify key concepts, research gaps, and types of evidence.

This mapping exercise involves systematically searching for, identifying, and charting relevant literature to understand its characteristics, such as the volume of research, types of studies conducted, key concepts addressed, and prevalent research gaps.

Unlike systematic reviews, which aim to answer specific questions, scoping reviews are exploratory and often used to assess the extent of available evidence and inform future research directions. They involve comprehensive searches and data extraction but do not typically include a detailed synthesis of findings or a critical appraisal of study quality.

When a scoping review methodology would be appropriate:

Scoping reviews can be used as a preliminary step to a systematic review , helping to identify the types of evidence available, potential research questions, and relevant inclusion criteria.

They can save time and resources by identifying potential challenges or limitations before embarking on a full systematic review.

Scoping reviews can help clarify key concepts/definitions in the literature. If a research area has inconsistent terminology or definitions, a scoping review can map out how different concepts are used and potentially propose a unified understanding. This can help refine the focus and scope of a subsequent systematic review.

• To determine if a systematic review is feasible and worthwhile . By identifying the breadth of evidence, researchers can gauge whether there is sufficient literature to warrant a full systematic review.
• To identify gaps in the existing research . Scoping reviews can highlight areas where little or no research has been conducted, helping inform future research priorities.
• To clarify key concepts and definitions in the field . This can help refine the focus and scope of a subsequent systematic review.
• To examine how research is conducted on a certain topic . This can inform the methodology of a future systematic review
• To refine and narrow down research questions . The broad overview provided by a scoping review can help researchers develop more specific, focused questions for a systematic review.

When not to choose a scoping review methodology:

• If a systematic review already exists on the topic: A systematic review will offer a more rigorous and comprehensive analysis of the evidence if one is already available.
• Examining the range of interventions for a health condition
• Identifying types of studies conducted
• Noting populations studied
• Summarizing outcomes measured

Scoping reviews help identify areas needing further research, whereas systematic reviews aim to draw conclusions about intervention effectiveness.

Methodological Guidelines

Methodological guidelines aim to improve the consistency and transparency of scoping reviews, enabling researchers to synthesize evidence effectively.

Methodological guidelines for scoping reviews have evolved over time:

• Arksey and O’Malley (2005) proposed the initial framework.
• Levac et al. (2010) refined and extended this framework, offering more detailed guidance.
• The Joanna Briggs Institute ( JBI ) further developed the methodology, introducing a more structured and transparent process.

1. Developing review objective(s) & question(s)

A well-defined objective and a set of aligned research questions are crucial for a scoping review’s coherence and direction.

They guide the subsequent steps of the review process, including determining the inclusion and exclusion criteria, developing a search strategy, and guiding data extraction and analysis.

This stage involves a thoughtful and iterative process to ensure that the review’s aims and questions are explicitly stated and closely intertwined.

Defining Objectives:

This step outlines the overarching goals of the scoping review. It explains the rationale behind conducting the review and what the reviewers aim to achieve.

The objective statement should succinctly capture the essence of the review and provide a clear understanding of its purpose.

For instance, a scoping review’s objective might be to map the existing literature on a particular topic and identify knowledge gaps.

“Parents, in particular, greatly influence participation at school, at home and in the community. They undertake many actions to improve their children’s participation in daily life. Understanding the actions of parents and also their challenges and needs will contribute to how society can support these parents and thereby enable the participation of children with physical disabilities. Pediatric rehabilitation, aiming for optimal participation, could benefit from this understanding to improve Family-centered services (FCS)… However, it is unclear what kind of information is available in literature about what parents live through, do, and what kind of problems and needs they have in supporting their child’s participation? For these reasons, a scoping review was conducted in order to systematically map the research done in this area, as well as to identify any existing gaps in knowledge”

Piškur, B., Beurskens, A. J., Jongmans, M. J., Ketelaar, M., Norton, M., Frings, C. A., … & Smeets, R. J. (2012). Parents’ actions, challenges, and needs while enabling participation of children with a physical disability: a scoping review.  BMC pediatrics ,  12 , 1-13.

Developing Research Questions:

The research question(s) stem from the objectives and provide a focused roadmap for the review. These questions should be answerable through the scoping review process. The research question(s) should be clear, concise, and directly relevant to the overall objectives.

Using Frameworks: While not mandatory, frameworks can be helpful tools to guide the development of objectives and research questions. Frameworks like PCC (Population, Concept, Context).

• Population: Clearly define the specific group of individuals or entities that the scoping review will focus on. This could be patients, healthcare professionals, or even organizations.
• Concept: Articulate the central idea, topic, or phenomenon that the review aims to investigate. This might include interventions, diagnostic tests, or theoretical models.
• Context: Specify the setting, environment, or circumstances relevant to the research question. This could involve geographical locations, healthcare systems, or cultural contexts.

How do cultural beliefs and practices ( C -context) influence the ways in which parents ( P -parents of children with physical disabilities) perceive and address ( C -concept) their children’s physical disabilities? 

What are the barriers and facilitators ( C -concept) to mental health service utilization ( C -concept) among veterans ( P -population) experiencing homelessness ( C -context)?

This scoping review aims to summarize what is known in the African scientific literature ( C -context) among cisgender persons ( P ) about a) individual experiences of GBS within health care settings ( C -concept) and b) associations between GBS experiences and health care-related outcomes ( C -concept).

What are the main theoretical and methodological characteristics ( C -concept) of the current literature ( C -context) in the area of stigma and hearing loss and stigma and hearing aids in the elderly population ( P -older adults with acquired hearing impairment), and how should future research proceed in expanding this important field of enquiry?

2. Write A Research Protocol

A research protocol is a detailed plan that outlines the methodology to be employed throughout the review process, detailing steps like documenting results, outlining search strategy, and stating the review’s objective

The protocol should be created a priori (before starting the review) to ensure transparency and reproducibility.

While not mandatory, registering your protocol is highly recommended, e.g. FigShare and Open Science Framework (OSF).

Some journals, such as the Journal of Advanced Nursing , Systematic Reviews , BMC Medical Research Methodology , BMJ Open , and JBI Evidence Synthesis , accept scoping review protocols for publication.

It’s important to note that PROSPERO, the international prospective register of systematic reviews, does not currently accept scoping review protocols for registration.

Registering a scoping review protocol is highly recommended, even if not mandatory, as it promotes transparency, reduces duplication of effort, and helps to prevent publication bias

Example Protocols:

• The nutritional care of people living with dementia at home: a protocol for a scoping study
• End-of-life care in long-term care homes: A scoping review protocol
• Delaying knee flexion following knee arthroplasty surgery: A Scoping Review Protocol

Report in the Methods Section

“Our protocol was drafted using the Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols (PRISMAP…), which was revised by the research team and members of Health Canada, and was disseminated through our programme’s Twitter account (@KT-Canada) and newsletter to solicit additional feedback. The final protocol was registered prospectively with the Open Science Framework on 6 September 2016 ( https://osf.io/kv9hu/ ).”

Tricco, A. C., Zarin, W., Lillie, E., Pham, B., & Straus, S. E. (2017). Utility of social media and crowd-sourced data for pharmacovigilance: a scoping review protocol.  BMJ open ,  7 (1), e013474.

“ Our protocol was developed using the scoping review methodological framework proposed by Arksey and O’Malley (2005) [1] and further refined by the Joanna Briggs Institute [3]. The draft protocol was revised upon receiving feedback from the research team, including methodologists and healthcare providers, as well as the peer-review panel of the Canadian Institutes of Health Research. The final version of the protocol is available upon request from the corresponding author. ”

Tricco, A. C., Lillie, E., Zarin, W., O’brien, K., Colquhoun, H., Kastner, M., … & Straus, S. E. (2016). A scoping review on the conduct and reporting of scoping reviews.  BMC medical research methodology ,  16 , 1-10.

3. Developing eligibility criteria

This step involves developing and aligning the inclusion criteria with the objective(s) and question(s).

By providing transparent and well-justified eligibility criteria, researchers can ensure the replicability of their scoping review and allow readers to assess the relevance and appropriateness of the included sources.

When reporting eligibility criteria, emphasize the importance of clarity, justification, and a clear link to the review’s objectives.

• Describe the eligibility criteria with a rationale for why they were selected : It’s crucial to clearly articulate the specific characteristics of sources that make them eligible for inclusion in the review. Each criterion should be accompanied by a rationale explaining why it was chosen. This rationale should be grounded in scientific arguments and clearly demonstrate how the criterion aligns with the review’s objectives.
• Identify specific restrictions and provide a rationale : Restrictions, such as date range, language, or publication status, also need clear justification. For instance, limiting the review to articles published within the past ten years might be necessary to capture the most current evidence. Similarly, restricting the review to sources in a specific language, like English, should be justified, acknowledging the potential exclusion of relevant research in other languages.

When specifying the inclusion and exclusion criteria, consider the following aspects:

By using the PCC framework, researchers can systematically establish boundaries for their scoping review, ensuring that the included sources are relevant to the research question. The framework helps to ensure that the eligibility criteria are comprehensive and well-defined, enabling a more focused and meaningful synthesis of the literature

• Population : The specific characteristics of the individuals or groups being studied. For instance, a scoping review about interventions for heart failure should specify the intended patient population (e.g., adults with heart failure, elderly patients with heart failure).
• Concept : This refers to the central idea, topic, or phenomenon under investigation. In the heart failure example, the concept could be “interventions for heart failure” itself, or it could be narrowed down to a specific type of intervention, such as “exercise interventions for heart failure.”
• Context : This element considers the setting or environment in which the concept is being explored. For instance, the context of the heart failure review could be “hospital settings,” “community-based care,” or “telehealth interventions.”

It is important to note that the absence of an explicitly stated framework (e.g. PCC) does not necessarily mean that the authors did not utilize a systematic approach when developing their eligibility criteria. It is possible that they employed a framework implicitly or that their criteria development was guided by other factors.

Iterative Process

The initial set of eligibility criteria outlined in the protocol may be subject to adjustments based on the type and volume of studies identified in the initial searches.

• Initial Development : Establish preliminary inclusion and exclusion criteria at the onset of the review based on their existing knowledge of the subject area. This can be adjusted as you become more familiar with the literature and data retrieved during the search process.
• Iterative Refinement : Inclusion criteria are refined iteratively based on pilot searches and the evolving understanding of the data. This initial search is crucial as it exposes researchers to a broader range of literature, revealing additional keywords, relevant concepts, and potentially useful search terms that might not have been initially considered.

“ Studies that identified the key terms in the title, abstract, article, or MeSH heading were retained for further examination. Studies published as abstracts, conference proceedings or pilot results published in non-peer-reviewed journals were excluded. In addition, books, book chapters, comments on publications, and dissertations were also excluded. No exclusion criteria were established regarding the type of research design. Inclusion criteria were (a) older adults with progressive hearing loss being the population of interest and (b) the outcome measure was clearly focused on (or at least on some aspects of) stigma regarding hearing loss and/or hearing aids. Although given the descriptive aim of the review, no definitions of stigma and/or hearing aids were set a priori, and all articles including these terms were retrieved, the analysis of the data relied on the most common dimensions of the concept of stigma cited in the literarture: the cognitive dimension (i.e., stereotypes), the emotional dimension (i.e., prejudice) and the behavioral dime. ”

• David, D., & Werner, P. (2016). Stigma regarding hearing loss and hearing aids: A scoping review.  Stigma and Health ,  1 (2), 59.

“ An extensive search was conducted to locate peer-reviewed articles that addressed questions related to parent involvement in organized youth sport. To guide article retrieval, two inclusion criteria were used. First, articles were required to highlight some form of parent involvement in organized youth sport. In the present study, organized youth sport was operationalized as “adultorganized and controlled athletic programs for young people,” wherein “participants are formally organized [and] attend practices and scheduled competitions under the supervision of an adult leader” (Smoll & Smith, 2002, p. xi). In line with this criterion, we did not include physical activity, exercise, physical education, and free play settings, which comprise a substantial volume of research in sport and exercise psychology. We also excluded research that simply collected data on parents or from parents but did not explicitly assess their involvement in their children’s sport participation. Second, articles were required to have been published in peer-reviewed, Englishlanguage, academic journals. As such, we did not include books, chapters, reviews, conceptual papers, conference proceedings, theses and (Jones, 2004) dissertations, or organizational “white papers” in this scoping review. ”

Dorsch, T. E., Wright, E., Eckardt, V. C., Elliott, S., Thrower, S. N., & Knight, C. J. (2021). A history of parent involvement in organized youth sport: A scoping review.  Sport, Exercise, and performance psychology ,  10 (4), 536.

“…to be included in the review, papers needed to measure or focus on specific dimensions of treatment burden, developed in the conceptual framework (e.g. financial, medication, administrative, lifestyle, healthcare and time/travel). Peer-reviewed journal papers were included if they were: published between the period of 2000–2016, written in English, involved human participants and described a measure for burden of treatment, e.g. including single measurements, measuring and/or incorporating one or two dimensions of burden of treatment. Quantitative, qualitative and mixed-method studies were included in order to consider different aspects of measuring treatment burden. Papers were excluded if they did not fit into the conceptual framework of the study, focused on a communicable chronic condition, for example human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) or substance abuse. Papers talking about carer burden, in addition to patient burden of treatment, were also included.”

Sav, A., Salehi, A., Mair, F. S., & McMillan, S. S. (2017). Measuring the burden of treatment for chronic disease: implications of a scoping review of the literature.  BMC medical research methodology ,  17 , 1-14.

4. Information Sources

Scoping reviews aim to identify a broad range of relevant studies, including both published and unpublished literature, to provide a comprehensive overview of the topic.

The goal is to be inclusive rather than exhaustive, which differentiates scoping reviews from systematic reviews that seek to collate all empirical evidence fitting pre-specified criteria to answer specific research questions.

Information sources for scoping reviews can include a wide range of resources like scholarly databases, unpublished literature, conference papers, books, and even expert consultations.

Report who developed and executed the search strategy, such as an information specialist or librarian. Mention if the search strategy was peer-reviewed using the Peer Review of Electronic Search Strategies (PRESS) checklist.

• Electronic   Databases : Make a comprehensive list of all electronic databases you used. Common databases for health-related scoping reviews include: CINAHL, Medline, Embase, PsycINFO, SocINDEX with Full Text, and Web of Science: Core Collections.
• Specify date ranges : For each database, note the date range of your search. For example: “MEDLINE was searched from inception to July 30, 2024.”
• Grey Literature : In addition to databases, forensic or ‘expansive’ searches can be conducted. This includes: grey literature database searches (e.g.  OpenGrey , WorldCat ,  Ethos ),  conference proceedings, unpublished reports,  theses  ,  clinical trial databases , searches by names of authors of relevant publications.
• Citation chasing : If you manually searched specific journals or reference lists, document this. For example: “We hand-searched the reference lists of all included studies and relevant systematic reviews.”
• Contacting Experts : If you contacted experts in the field for additional sources, mention this: “We contacted five experts in the field of [topic] to identify any additional relevant studies.”

“To identify potentially relevant documents, the following bibliographic databases were searched from 2004 to June 2015: MEDLINE, EMBASE, LexisNexis Academic, the Legal Scholarship Network, Justis, LegalTrac, QuickLaw, and HeinOnline. The search strategies were drafted by an experienced librarian [name] and further refined through team discussion. The final search strategy for MEDLINE can be found in Additional file 3. The final search results were exported into EndNote, and duplicates were removed by a library technician. The electronic database search was supplemented by searching the Canadian Medical Protective Association website (https://www.cmpa-acpm.ca/en) and scanning relevant reviews.”

Cardoso, R., Zarin, W., Nincic, V., Barber, S. L., Gulmezoglu, A. M., Wilson, C., … & Tricco, A. C. (2017). Evaluative reports on medical malpractice policies in obstetrics: a rapid scoping review.  Systematic reviews ,  6 , 1-11.

5. Searching for the evidence

Scoping reviews typically start with a broader, more inclusive search strategy. The initial search is intentionally wide-ranging to capture the breadth of available literature on the topic

To balance breadth and depth in your initial search strategy for a scoping review, consider the following tips based on the gathered search results:

• Start with a broad initial search : Begin with a broad search across at least two relevant databases (e.g., MEDLINE and Scopus) to capture a wide range of literature. This helps identify the scope of available studies and key themes in the field .
• Test and refine your search strategy : After initial searches, review the titles and abstracts of retrieved articles to assess relevance. Analyze the text words and index terms used in these articles to refine your understanding of the topic and identify additional keywords, synonyms, and subject headings to include in subsequent searches .
• Multiple Databases : Search across a variety of databases to ensure a comprehensive literature capture. Each database may index different journals and articles, which can help broaden your search results .
• Boolean operators:  The use of Boolean operators (AND/OR/NEAR/NOT) helps to combine these terms effectively, ensuring that the search strategy is both sensitive and specific. For instance, using “AND” narrows the search to include only results containing both terms, while “OR” expands it to include results containing either term.
• Truncation symbols : These broaden the search by capturing variations of a keyword. They function by locating every word that begins with a specific root. For example, if a user was researching interventions for smoking, they might use a truncation symbol to search for “smok*” to retrieve records with the words “smoke,” “smoker,” “smoking,” or “smokes.” This can save time and effort by eliminating the need to input every variation of a word into a database.
• Citation chasing : Document the specific studies whose reference lists were examined. Include the titles, authors, and publication years of these studies. Note how you identified articles that cite the studies. This could be through citation databases like Google Scholar, Scopus, or Web of Science.
• Detailed documentation : Keep thorough records of your search strategies, including the databases searched, keywords used, and any filters applied. This documentation is crucial for transparency and reproducibility .

” The planned literature search was developed on June 23, 2022. The inclusion and exclusion criteria were further refined, along with electronic databases to identify psychological and education literature (e.g., ProQuest), programs for storing data (i.e., Covidence, n.d. accessed via https://www.covidence.org/) and key search terms (e.g., resistance and transgender). The key search terms were “transgender/trans/LGBT/gender diverse/gender expansive/nonbinary,” “resistance,” and “faith/economic status/ethnicity/gender.” Daniel Abela used terms such as nonbinary, gender diverse, LGBT, and gender expansive to capture the broad spectrum of language employed in the literature when relating to individuals whose gender identification extends beyond conventional norms associated with their assigned sex at birth. Moreover, the authors wanted a diverse sample through an intersectionality lens; therefore, terms such as faith, economic status, and ethnicity were used. These terms were selected as they were deemed by all authors to be most appropriate to evaluate this study’s research question. A complete list of the final search terms and the entire electronic search strategy for the Ovid database are presented in Table 1. ”

Abela, D., Patlamazoglou, L., & Lea, S. (2024). The resistance of transgender and gender expansive people: A scoping review.  Psychology of Sexual Orientation and Gender Diversity .

Ovid Search Strategy (Table 1)

• transgender.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• trans.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• LGBT.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• gender diverse.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• gender expansive.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• non-binary.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• 1 or 2 or 3 or 4 or 5 or 6
• resistance.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• faith.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• economic status.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• ethnicity.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• gender identification.mp. [mp = title, abstract, heading word, table of contents, key concepts, original title, tests & measures, mesh word]
• 10 or 11 or 12 or 13
• limit 15 to (peer-reviewed journal and English language and “0110 peer-reviewed journal” and English and yr = “2012-Current”)

Search strategy can also be reported in the appendix. For example: Supplementary A: Search strategy for scoping review .

Citation Chasing Process

Citation chasing involves reviewing the reference lists of included studies and examining articles that cite those studies to identify additional relevant literature. This process helps ensure that you capture a comprehensive view of the research landscape.

If citation chasing leads to the identification of new keywords or concepts, document these adjustments and how they were incorporated into the overall search strategy.

• Document the rationale : Clearly state why citation chasing is being conducted. This could include the goal of identifying additional studies that may not have been captured through database searches or to explore the context and impact of key studies.
• Reference list review : Document the specific studies whose reference lists were examined. Include the titles, authors, and publication years of these studies.
• Citing articles : Note how you identified articles that cite the studies. This could be through citation databases like Google Scholar, Scopus, or Web of Science.
• Record number of additional studies identified : Keep a count of how many additional studies were found through citation chasing.
• A flowchart : Adapt the PRISMA flow diagram to illustrate the stages of citation chasing, the number of sources identified at each stage, and reasons for exclusion.
• Tables : Summarize key information about the sources identified through citation chasing, such as author, year, title, and reasons for inclusion or exclusion.

6. Selecting the evidence

While articles included in a scoping review are selected systematically, it is important to acknowledge that there is no assumption that the evidence reviewed is exhaustive. This is often due to limitations in the search strategy or difficulty locating specific types of sources.

The search results are screened against pre-defined eligibility criteria to determine inclusion in the review.

The goal is to identify relevant studies, with less emphasis on methodological quality. Scoping reviews generally do not appraise the quality of included studies.

Instead, scoping reviews prioritize mapping the existing literature and identifying gaps in research, regardless of the quality of the individual studies.

Two reviewers should independently screen titles and abstracts, removing duplicates and irrelevant studies based on predefined inclusion and exclusion criteria.

• Initial screening of titles and abstracts:  After applying a strategy to search the literature, the next step involves screening the titles and abstracts of the identified articles against the predefined inclusion and exclusion criteria. During this initial screening, reviewers aim to identify potentially relevant studies while excluding those clearly outside the scope of the review. It is crucial to prioritize over-inclusion at this stage, meaning that reviewers should err on the side of keeping studies even if there is uncertainty about their relevance. This cautious approach helps minimize the risk of inadvertently excluding potentially valuable studies.
• Retrieving and assessing full texts:  For studies which a definitive decision cannot be made based on the title and abstract alone, reviewers need to obtain the full text of the articles for a comprehensive assessment against the predefined inclusion and exclusion criteria. This stage involves meticulously reviewing the full text of each potentially relevant study to determine its eligibility definitively.
• Resolution of disagreements : In cases of disagreement between reviewers regarding a study’s eligibility, a predefined strategy involving consensus-building discussions or arbitration by a third reviewer should be in place to reach a final decision. This collaborative approach ensures a fair and impartial selection process, further strengthening the review’s reliability.

“To increase consistency among reviewers, all reviewers screened the same 50 publications, discussed the results and amended the screening and data extraction manual before beginning screening for this review. Nine reviewers working in pairs sequentially evaluated the titles, abstracts and then full text of all publications identified by our searches for potentially relevant publications. . . . We resolved disagreements on study selection and data extraction by consensus and discussion with other reviewers if needed.”

Duffett, M., Choong, K., Hartling, L., Menon, K., Thabane, L., & Cook, D. J. (2013). Randomized controlled trials in pediatric critical care: a scoping review.  Critical care ,  17 , 1-9.

7. Extracting the evidence

Charting, also known as data extraction, is a crucial stage in conducting a scoping review.

This process involves systematically collecting relevant information from the sources included in the review using a structured form. It is considered best practice to have at least two reviewers independently extract data from each source

Data charting in scoping reviews differs from data extraction in systematic reviews. While systematic reviews aim to synthesize the results and assess the quality of individual studies, scoping reviews focus on mapping the existing literature and identifying key concepts, themes, and gaps in the research.

Therefore, the data charting process in scoping reviews is typically broader in scope and may involve collecting a wider range of data items compared to the more focused data extraction process used in systematic reviews.

This process goes beyond simply extracting data; it involves characterizing and summarizing research evidence, which ultimately helps identify research gaps.

• Develop a Standardized Form: Creating a structured form helps to standardize the selection of sources. The form should incorporate clear questions that align with the eligibility criteria defined in the review protocol. The specific software used to create and manage the form should be specified in the review, with options such as Covidence , EndNote , or JBI SUMARI .
• Year of publication
• Origin/country of origin (where the study was published or conducted)
• Aims/purpose
• Study population and sample size (if applicable)
• Methodology/methods
• Outcomes and details of these (e.g. how measures) (if applicable)
• Key findings that relate to the scoping review question/s.
• Testing the Form: All reviewers involved in the selection process should participate in testing the standardized form. Screen the titles and abstracts of the identified articles against the predefined inclusion and exclusion criteria. 
• Sample Size: A random sample of 5–10 citations can be used for the initial calibration of title and abstract screening.
• Resolving Inconsistencies: After independent screening, discrepancies between reviewers are identified and discussed. A roundtable discussion involving the review team is an effective method to address these inconsistencies and clarify any ambiguities in the form or eligibility criteria.
• Form Refinement: Based on the calibration exercise, the standardized form and its accompanying explanation should be revised and refined as needed to enhance clarity and consistency. A second calibration exercise might be necessary if the desired agreement level, typically 70%–80%, is not achieved or if reviewers require further training.
• Number of Reviewers: A minimum of two independent reviewers should be engaged in the screening process.
• Duplicate Screening: The review process should clearly state how duplicates were managed, ideally removing them before proceeding to the screening stage.
• Verification: The sources describe different approaches to verification, including independent screening by two reviewers followed by comparison of their results or a single reviewer screening followed by verification from another reviewer. The chosen approach and its rationale should be explicitly stated in the scoping review.
• Resolving Disagreements: Any disagreements arising during the screening process should be documented and resolved, ideally through discussion and consensus among the reviewers. If consensus cannot be reached, involving a third reviewer to provide an independent assessment can help in making the final decision.
• The number of reviewers involved at each stage
• How duplicates were addressed
• The software used to manage the screening process
• How disagreements were resolved
• The number of sources excluded at each stage, along with a clear rationale for their exclusion

“Search results for all databases were merged. Duplicates and nonrelated papers were excluded. Titles and abstracts of the remaining papers were assessed against the inclusion and exclusion criteria independently by both authors. The resulting papers were pooled and disagreements were resolved through discussion based on the full text article. Following this stage, a standardized form was used to summarize the information in each article. The variables extracted were: reference/ country, aim of the study, study design, year of publication, and main finding/results.”

“A data-charting form was jointly developed by two reviewers to determine which variables to extract. The two reviewers independently charted the data, discussed the results and continuously updated the data-charting form in an iterative process.”

Lenzen, S. A., Daniëls, R., van Bokhoven, M. A., van der Weijden, T., & Beurskens, A. (2017). Disentangling self-management goal setting and action planning: A scoping review.  PloS one ,  12 (11), e0188822.

If an article was eligible for inclusion in this study, data related to the patient-centered care framework or model presented in the article was extracted by the lead author and reviewed by a second author (JCM). Data extracted from the reviewed patient-centered care frameworks and models was entered into data extraction records and synthesized in summary format. Data were systematically charted using the data charting form developed in Microsoft Excel. Information on authorship, article type, population, and patientcentered care approach were recorded on this form. A second data charting form was developed to chart data on the communication systematic reviews identified. Information on clinical context, patient-centered care focus, number of studies reviewed and key findings were recorded on this form.

Constand, M. K., MacDermid, J. C., Dal Bello-Haas, V., & Law, M. (2014). Scoping review of patient-centered care approaches in healthcare.  BMC health services research ,  14 , 1-9.

The final charting form, which clearly defines each item, should be included in the scoping review as an appendix or supplementary file, if possible.

• Author: This information is essential for referencing and should be consistent throughout the scoping review document.
• Year of Publication: Noting the publication year of each source helps analyze trends and changes in research over time. This variable can highlight areas where research has progressed or where further investigation is necessary.
• Country: This variable involves noting the country of the study and the bibliographic details of each source. The country of origin provides context and helps assess the generalizability of findings to other settings.
• Objective(s): The objectives of each included source of evidence should be clearly stated. This variable helps understand the aim of each study and how it contributes to the overall scoping review question.
• Participants (characteristics/total number): This variable involves describing the defining characteristics of the participants in the included sources of evidence. Details like diagnostic criteria, age, ethnicity, and the total number of participants are crucial elements of this variable. This information provides context to the scoping review findings.
• Concept: This variable pertains to extracting and mapping data related to the core concept being investigated in the scoping review. The specific data extracted will depend on the nature of the concept, which should be clearly defined in the scoping review.
• Intervention Type: If applicable to the scoping review question, the type of intervention used in each source should be recorded. This might include details like the specific intervention method, the comparator used, and the duration of the intervention. This information helps compare and contrast different interventions explored in the included studies.
• Methodology: Describing the methodology employed by each source is essential to understand how the research was conducted. This variable provides insights into the study design, data collection methods, and analysis techniques used. Categorizing study designs is essential to compare and contrast different research approaches and their potential implications for the scoping review’s conclusions.
• Outcome Measures: This variable focuses on the tools or methods used to assess the effects of an intervention or phenomenon. It’s essential to describe the specific outcome measures used in each study, including details on how they were measured. This information helps compare findings across studies using similar outcome assessment tools.
• Main Finding: This variable focuses on extracting the primary findings or results of each study that are relevant to the scoping review’s research question. These findings form the core evidence base and are crucial for addressing the scoping review objectives.

“We abstracted data on article characteristics (e.g., country of origin, funder), engagement characteristics and contextual factors (e.g., type of knowledge user, country income level, type of engagement activity, frequency and intensity of engagement, use of a framework to inform the intervention), barriers and facilitators to engagement, and results of any formal assessment of engagement (e.g., attitudes, beliefs, knowledge, benefits, unintended consequences).”

Tricco, A. C., Zarin, W., Rios, P., Nincic, V., Khan, P. A., Ghassemi, M., … & Langlois, E. V. (2018). Engaging policy-makers, health system managers, and policy analysts in the knowledge synthesis process: a scoping review.  Implementation Science ,  13 , 1-19.

8. Analyzing the evidence

The key element of a scoping review is the synthesis: that is the process that brings together the findings from the set of included studies in order to draw conclusions based on the body of evidence.

Data synthesis in a scoping review involves collating, combining, and summarizing findings from the included studies.

This process aims to provide a reliable and comprehensive answer to the review question by considering the strength of the evidence, examining the consistency of observed effects, and investigating any inconsistencies.

The data synthesis will be presented in the results section of the scoping review.

• Develop a clear text narrative that explains the key findings
• Use a logical heading structure to guide readers through your results synthesis
• Use tables to summarise findings (can be same table as data extraction)

Scoping reviews often use a more descriptive approach to synthesis, summarizing the types of evidence available, key findings, and research gaps.

• Research design (e.g., experimental, observational, qualitative)
• Population characteristics
• Intervention types
• Outcome measures
• Theoretical frameworks
• Geographic regions
• Time periods
• The predominant study designs used in the field
• The range of methodologies employed
• The diversity (or lack thereof) in research approaches
• Primary outcomes
• Major conclusions drawn by the authors
• Any notable or unexpected findings
• Recurring themes in the literature
• Evolving research focuses over time
• Commonly used methodologies or theoretical frameworks
• Consistency (or inconsistency) in findings across different studies
• Identifying areas that have been extensively studied
• Noting topics that have received less attention
• Highlighting any shifts in research focus over time
• Populations that have been understudied
• Methodologies that haven’t been widely applied
• Questions that remain unanswered or inadequately addressed
• Contradictions in the literature that need further investigation
• Summarizing key concepts: Identify and describe the central ideas, theories, or constructs that emerge from the literature. This helps to provide a conceptual overview of the field.
• Tables summarizing study characteristics
• Charts showing the distribution of studies across categories
• Concept maps illustrating relationships between key ideas

Remember, the goal in a scoping review is not to critically appraise the quality of individual studies or to provide a definitive answer to a narrow research question.

Instead, the synthesis aims to provide a broad overview of the field, mapping out the existing literature and identifying areas for further research.

This descriptive approach allows for a comprehensive understanding of the landscape of a particular research area.

“We grouped the studies by the types of behavior they analyzed, and summarized the type of settings, populations and study designs for each group, along with the measures used and broad findings. Where we identified a systematic review, we counted the number of studies included in the review that potentially met our inclusion criteria and noted how many studies had been missed by our search.”

Hutchinson, J., Prady, S. L., Smith, M. A., White, P. C., & Graham, H. M. (2015). A scoping review of observational studies examining relationships between environmental behaviors and health behaviors.  International journal of environmental research and public health ,  12 (5), 4833-4858.

9. Presenting the results

The findings should be presented in a clear and logical way that answers the research question(s). This section might include tables, figures, or narrative summaries to illustrate the data.

Narrative Summaries

Write a clear, concise narrative that brings together all of these elements. This should provide readers with a comprehensive overview of the current state of knowledge in the field, highlighting both what is known and what remains to be explored.

The primary goal of a narrative summary is to weave together the information extracted from multiple sources into a cohesive and understandable narrative. This story should focus on why a specific action is necessary, should be discontinued, or lacks sufficient evidence to determine its efficacy

A well-crafted narrative summary often utilizes headings and subheadings to organize the synthesized information logically.

This approach makes it easier for readers to follow the thought process and understand the relationships between different pieces of evidence.

Strategies on how to be sensitive to patient needs were primarily discussed in the qualitative research articles included in this review. Such strategies included acknowledging and adapting to unique patient identifiers [19,24,25]. For example, clinicians are urged to observe and reflect on fluctuating levels of patient alertness, patient comfort levels in the presence or absence of family members, and different communication barriers such as hearing loss, in order to facilitate clinical interactions [15,19,22]. Of the articles reviewed, 58% identified that careful observation of unique patient characteristics is necessary to providing care that will lead to optimal patient receptiveness and positive health outcomes.

While narrative summaries primarily use text, incorporating tables, charts, or diagrams can enhance clarity, particularly when presenting complex data patterns.

However, always accompany these visual aids with a clear textual explanation to ensure comprehensive understanding.

PRISMA Flowchart

Using a PRISMA flowchart in a scoping review is considered good practice. It promotes transparency and allows for a clear understanding of how sources were selected.

The flowchart illustrates the step-by-step process of screening, filtering, and selecting studies based on predefined inclusion and exclusion criteria.

The flowchart visually depicts the following stages:

• Identification:  The initial number of titles and abstracts identified through database searches.
• Screening:  The screening process, based on titles and abstracts.
• Eligibility:  Full-text copies of the remaining records are retrieved and assessed for eligibility.
• Inclusion:  Applying the predefined inclusion criteria resulted in the inclusion of publications that met all the criteria for the review.
• Exclusion:  The flowchart details the reasons for excluding the remaining records.

Petersen, B., Koshy-Chenthittayil, S., DeArmond, M., & Caromile, L. A. (2023). Assessment of diversity-based approaches used by American Universities to increase recruitment and retention of biomedical sciences research faculty members: A scoping review protocol.  Plos one ,  18 (6), e0276089.

10. Discussion Section And Conclusion

Summarizing the evidence in relation to the purpose of the review, making conclusions and noting any implications of the findings.

It is also essential to remember that scoping reviews, unlike systematic reviews, do not aim to provide concrete recommendations for practice or policy.

Their primary function is to map the existing evidence, identify knowledge gaps, and clarify concepts, rather than synthesize results for direct application in clinical or policy settings

Summarizing the Evidence

• Summarize key findings in relation to your research questions
• Highlight main themes or patterns across studies
• Explain the nuances and complexities in the evidence
• Tailor overall findings of the scoping review to the relevant knowledge users such as policymakers, health care providers and patients or consumers
• Discuss the consistency of the evidence
• This provides a clear takeaway message for readers

“In this scoping review we identified 88 primary studies addressing dissemination and implementation research across various settings of dementia care published between 1998 and 2015. Our findings indicate a paucity of research focusing specifically on dissemination of knowledge within dementia care and a limited number of studies on implementation in this area. We also found that training and educating professionals, developing stakeholder interrelationships, and using evaluative and iterative strategies are frequently employed to introduce and promote change in practice. However, although important and feasible, these strategies only partly address what is repeatedly highlighted in the evidence base: that organisational factors are reported as the main barrier to implementation of knowledge within dementia care. Moreover, included studies clearly support an increased effort to improve the quality of dementia care provided in residential settings in the last decade.”

Lourida, I., Abbott, R. A., Rogers, M., Lang, I. A., Stein, K., Kent, B., & Thompson Coon, J. (2017). Dissemination and implementation research in dementia care: a systematic scoping review and evidence map.  BMC geriatrics ,  17 , 1-12.

Limitations

When considering the limitations of a review process, particularly scoping reviews, it’s essential to acknowledge that the goal is breadth, not depth, of information.

This means that unlike systematic reviews, scoping reviews generally don’t involve a formal appraisal of the methodological quality of included studies, unless specifically required by the review’s aim.

• One significant limitation frequently encountered in reviews is the restriction to English-language sources. This decision, often made for feasibility, can inadvertently introduce bias by excluding valuable research from non-English speaking communities and potentially limiting the generalizability of the findings.
• For instance, if a scoping review protocol initially excludes gray literature but later incorporates it due to the emergence of relevant findings during the review process, this change needs to be explicitly stated and justified in the final report.

“Our scoping review has some limitations. To make our review more feasible, we were only able to include a random sample of rapid reviews from websites of rapid review producers. Further adding to this issue is that many rapid reviews contain proprietary information and are not publicly available. As such, our results are only likely generalizable to rapid reviews that are publicly available. Furthermore, this scoping review was an enormous undertaking and our results are only up to date as of May 2013.”

Tricco, A. C., Antony, J., Zarin, W., Strifler, L., Ghassemi, M., Ivory, J., … & Straus, S. E. (2015). A scoping review of rapid review methods.  BMC medicine ,  13 , 1-15.

Conclusions

Discuss implications:.

• Note that recommendations for practice and policy will not be relevant for most scoping reviews as the goal is to provide a preliminary map of the evidence without appraising the quality and validity of the results.
• Consider both positive and negative implications.
• This helps translate your findings into real-world applications.

Identify gaps and future research:

• Point out areas where evidence is lacking or inconsistent.
• Suggest specific research questions or study designs to address these gaps.
• Recommendations for future research are often a key element, particularly suggestions for more focused systematic reviews based on the scoping review’s findings.
• For instance, a scoping review might reveal a need for research linking specific features of expertise to mental and physical health outcomes. Similarly, there might be methodological gaps regarding the validation of certain measures or understanding experiences across diverse contexts and populations.

“The lack of evidence to support physiotherapy interventions for this population appears to pose a challenge to physiotherapists. The aim of this scoping review was to identify gaps in the literature which may guide a future systematic review. However, the lack of evidence found means that undertaking a systematic review is not appropriate or necessary […]. This advocates high quality research being needed to determine what physiotherapy techniques may be of benefit for this population and to help guide physiotherapists as how to deliver this.”

Hall, A. J., Lang, I. A., Endacott, R., Hall, A., & Goodwin, V. A. (2017). Physiotherapy interventions for people with dementia and a hip fracture—a scoping review of the literature.  Physiotherapy ,  103 (4), 361-368.

Potential Challenges

• Balancing breadth and depth: Scoping reviews necessitate a careful balance between covering a wide range of literature (breadth) and providing sufficient depth of analysis. A scope that is too broad can become unmanageable and result in superficial treatment of the topic. Conversely, excessive focus on depth might compromise the comprehensiveness of the review. This balance requires careful consideration during the planning stages, particularly when defining the review question and inclusion criteria.
• Lack of standardized terminology and methods: While frameworks for scoping reviews exist, there is still a lack of consensus on terminology and methods, potentially leading to inconsistencies in how they are conducted and reported. This variability can make it challenging to assess the quality and reliability of scoping review findings.
• Difficulty in analyzing and presenting findings: Scoping reviews often involve synthesizing information from a large and diverse body of literature. Analyzing and presenting this information in a meaningful and concise way can be demanding, requiring a high level of analytical skill and clarity of presentation. The absence of standardized analysis methods further exacerbates this challenge, leading to potential inconsistencies in how data is extracted, analyzed, and presented.
• Limited resources and time constraints: Scoping reviews, although sometimes perceived as a quicker alternative to systematic reviews, can still be resource-intensive. They require meticulous planning, comprehensive searching, and rigorous analysis.

Reading List

• Arksey, H., & O’Malley, L. (2005). Scoping studies: towards a methodological framework .  International journal of social research methodology ,  8 (1), 19-32.
• Levac, D., Colquhoun, H., & O’brien, K. K. (2010). Scoping studies: advancing the methodology .  Implementation science ,  5 , 1-9.
• Munn, Z., Peters, M. D., Stern, C., Tufanaru, C., McArthur, A., & Aromataris, E. (2018). Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach.  BMC medical research methodology ,  18 , 1-7.
• Pearson, A., Wiechula, R., & Lockwood, C. (2005). The JBI model of evidence-based healthcare.  JBI Evidence Implementation ,  3 (8), 207-215.
• Peters, M. D., Godfrey, C., McInerney, P., Munn, Z., Tricco, A. C., & Khalil, H. (2020). Scoping reviews .  JBI manual for evidence synthesis ,  10 .
• Peters, M., Godfrey, C., McInerney, P., Soares, C. B., Khalil, H., & Parker, D. (2015). Methodology for JBI scoping reviews. In  The Joanna Briggs institute reviewers manual 2015  (pp. 3-24). Joanna Briggs Institute.
• Peters, M., Godfrey, C., Khalil, H., McInerney, P., Soares, C., & Parker, D. (2017). 2017 guidance for the conduct of JBI scoping reviews .  Joana Briggs Inst Rev Man ,  13 , 141-6.
• Pollock, D., Davies, E. L., Peters, M. D., Tricco, A. C., Alexander, L., McInerney, P., … & Munn, Z. (2021). Undertaking a scoping review: A practical guide for nursing and midwifery students, clinicians, researchers, and academics .  Journal of advanced nursing ,  77 (4), 2102-2113.
• Pollock, D., Peters, M. D., Khalil, H., McInerney, P., Alexander, L., Tricco, A. C., … & Munn, Z. (2023). Recommendations for the extraction, analysis, and presentation of results in scoping reviews.  JBI evidence synthesis ,  21 (3), 520-532.
• Scott, H., Sweet, L., Strauch, L., & Muller, A. (2019). Expressed breastmilk handling and storage guidelines available to mothers in the community: A scoping review. Women and Birth, 33 (5), 426–432.
• Tricco, AC, Lillie, E, Zarin, W, O’Brien, KK, Colquhoun, H, Levac, D, Moher, D, Peters, MD, Horsley, T, Weeks, L, Hempel, S et al. PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation. Ann Intern Med. 2018,169(7):467-473.

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How can soil quality be accurately and quickly studied a review.

1. Introduction

2. soil quality definitions and evaluation, 3. soil quality index, 4. soil quality indicators, 5. approaches to soil quality assessment, 5.1. conventional approaches, 5.2. novel approaches, 5.2.1. gis and rs, 5.2.2. artificial intelligence, machine learning, and deep learning.

• The characteristics of the studied sectors: to cover all anticipated capabilities, the sectors being studied must be consistent with one another.
• The precision with which training sample analyses are conducted.
• The precision with which soil quality is calculated in order to prepare data for testing and training
• Select the right model and modify model parameters to obtain the highest efficiency in the least amount of time.
• Firstly, the experimental results of soil indicators for the different samples are included as inputs.
• Then, each indicator score is ranked according to [ 136 ].
• A unique database is created to gather the scores for each indicator in the various study samples.
• The methodology for calculating the soil quality indices is thoroughly detailed in [ 136 ].
• The final soil quality index (FSQI) is determined at this stage using the formula outlined in [ 136 ].
• The FSQI values for all samples are categorized.
• Finally, a new database is constructed containing the FSQI result classes for every sample under investigation.
• Deep learning uses handcrafted features, while conventional pattern automatically extracts features from large data sets [ 171 ].
• Over the course of five to ten years, just one widely acknowledged good feature has arisen in the history of computer vision development.
• Nonetheless, deep learning may swiftly learn new, useful feature representations from training data in order to pursue new uses.
• The space of applications that can be implemented with this simple strategy is nearly infinite.
• Many more applications are completely out of reach for current deep learning techniques—even given vast amounts of human-notated data. You could not train a deep learning model to only read a product description and produce the right codebases with this data. It must be pre-processed.
• It is quite hard to train a sorting algorithm using a deep neural network. Because a deep learning model is “just” a series of straightforward, continuous geometric transformations that translate one vector space into another.
• A deep neural network that can accomplish the task on a practical scale would be much too complicated.

6. Case Studies in Some Egyptian Soils

7. conclusions, data availability statement, conflicts of interest.

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El Behairy, R.A.; El Arwash, H.M.; El Baroudy, A.A.; Ibrahim, M.M.; Mohamed, E.S.; Kucher, D.E.; Shokr, M.S. How Can Soil Quality Be Accurately and Quickly Studied? A Review. Agronomy 2024 , 14 , 1682. https://doi.org/10.3390/agronomy14081682

El Behairy RA, El Arwash HM, El Baroudy AA, Ibrahim MM, Mohamed ES, Kucher DE, Shokr MS. How Can Soil Quality Be Accurately and Quickly Studied? A Review. Agronomy . 2024; 14(8):1682. https://doi.org/10.3390/agronomy14081682

El Behairy, Radwa A., Hasnaa M. El Arwash, Ahmed A. El Baroudy, Mahmoud M. Ibrahim, Elsayed Said Mohamed, Dmitry E. Kucher, and Mohamed S. Shokr. 2024. "How Can Soil Quality Be Accurately and Quickly Studied? A Review" Agronomy 14, no. 8: 1682. https://doi.org/10.3390/agronomy14081682

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• Identifying evidence-practice gaps for shoulder injury risk factors in competitive swimmers: uniting literature and expert opinion
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• http://orcid.org/0000-0003-1071-4958 Alec Kenneth McKenzie 1 , 2 ,
• http://orcid.org/0000-0003-2908-4271 Andrea Hams 2 , 3 ,
• http://orcid.org/0000-0002-7591-1162 Jonathon Headrick 2 ,
• http://orcid.org/0000-0003-4764-2361 Alex Donaldson 4 ,
• http://orcid.org/0000-0003-1269-4612 Rick Dann 2 ,
• http://orcid.org/0000-0002-5855-4298 Joseph Coyne 5 , 6 ,
• http://orcid.org/0000-0002-4014-7731 Steven John Duhig 2
• 1 Queensland Academy of Sport , Brisbane , Queensland , Australia
• 2 School of Health Sciences and Social Work , Griffith University , Gold Coast , Queensland , Australia
• 3 Griffith Centre of Biomedical and Rehabilitation Engineering (GCORE) , Griffith University , Gold Coast , Queensland , Australia
• 4 Centre for Sport and Social Impact , LaTrobe University , Melbourne , Victoria , Australia
• 5 Bond University , Robina , Queensland , Australia
• 6 University of Southern Queensland , Toowoomba , Queensland , Australia
• Correspondence to Alec Kenneth McKenzie; alec.mckenzie2{at}griffithuni.edu.au

Objectives To identify evidence-practice gaps regarding shoulder injury risk factors in competitive swimmers.

Methods We gathered insights from 27 swimming experts including elite swimmers, coaches, high-performance staff and applied researchers using Concept Mapping. Participants brainstormed, sorted and rated (from 1 (least) to 10 (most) important and modifiable) their ideas of shoulder injury risk factors in competitive swimmers. Proposed risk factors rated above the grand mean for importance (6.2±0.4) or modifiability (6.5±0.5) ratings were considered highly important/modifiable. Expert opinions were then juxtaposed with systematic review findings to identify overlaps or convergences.

Results Brainstorming generated 126 proposed shoulder injury risk factors for competitive swimmers, subsequently refined to 61 unique proposed risk factors by removing duplicates and combining similar responses. The participants sorted the 61 risk factors into seven distinct clusters. Experts perceived 36/61 proposed risk factors as highly important, of which 6 were supported by literature, 6 showed no association with injury, 2 had conflicting evidence and the remaining 22 have not yet been investigated, suggesting an evidence-practice gap. Three proposed risk factors ‘inconsistent training load’, ‘poor stroke technique’ and ‘low posterior shoulder strength-endurance’ exhibited high perceived importance, high perceived modifiability and supporting evidence.

Conclusion An evidence-practice gap was identified for 28 proposed risk factors perceived as highly important by swimming experts despite either (1) no relevant empirical research (n=22), or (2) no association with injury (n=6) from synthesised evidence. Greater collaboration between researchers and practitioners is needed to effectively address shoulder injury risk factors in competitive swimmers.

• Sporting injuries
• Risk factor

Data availability statement

Data are available upon reasonable request. All collected data is presented in-text. Please email corresponding author for any further information.

https://doi.org/10.1136/bjsports-2023-108023

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X @a_k_mckenzie, @andrea_hams, @Jon_Headrick, @AlexDonaldson13, @josephcoyne, @duhigs

Contributors This study was part of AKM's (guarantor) research programme supervised by SJD, AH and JH. AD provided expert guidance on concept mapping methodologies. JC provided practical input as an elite swimming strength and conditioning practitioner. RD aided with concept mapping analysis, data synthesis and manuscript drafting.

Funding This project was funded by a $A3000 grant award by Swimming Australia.

Competing interests None declared.

Patient and public involvement Patients and/or the public were involved in the design, or conduct, or reporting, or dissemination plans of this research. Refer to the Methods section for further details.

Provenance and peer review Not commissioned; externally peer reviewed.

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