example of synthesized literature review

The Sheridan Libraries

• Write a Literature Review
• Sheridan Libraries
• Evaluate This link opens in a new window

Get Organized

• Lit Review Prep Use this template to help you evaluate your sources, create article summaries for an annotated bibliography, and a synthesis matrix for your lit review outline.

Synthesize your Information

Synthesize: combine separate elements to form a whole.

Synthesis Matrix

A synthesis matrix helps you record the main points of each source and document how sources relate to each other.

After summarizing and evaluating your sources, arrange them in a matrix or use a citation manager to help you see how they relate to each other and apply to each of your themes or variables.  

By arranging your sources by theme or variable, you can see how your sources relate to each other, and can start thinking about how you weave them together to create a narrative.

• Step-by-Step Approach
• Example Matrix from NSCU
• Matrix Template
• << Previous: Summarize
• Next: Integrate >>
• Last Updated: Jul 30, 2024 1:42 PM
• URL: https://guides.library.jhu.edu/lit-review

• University of Oregon Libraries
• Research Guides

How to Write a Literature Review

• 6. Synthesize
• Literature Reviews: A Recap
• Reading Journal Articles
• Does it Describe a Literature Review?
• 1. Identify the Question
• 2. Review Discipline Styles
• Searching Article Databases
• Finding Full-Text of an Article
• Citation Chaining
• When to Stop Searching
• 4. Manage Your References
• 5. Critically Analyze and Evaluate

Synthesis Visualization

Synthesis matrix example.

• 7. Write a Literature Review

• Synthesis Worksheet

About Synthesis

Approaches to Synthesis

You can sort the literature in various ways, for example:

How to Begin?

Read your sources carefully and find the main idea(s) of each source

Look for similarities in your sources – which sources are talking about the same main ideas? (for example, sources that discuss the historical background on your topic)

Use the worksheet (above) or synthesis matrix (below) to get organized

This work can be messy. Don't worry if you have to go through a few iterations of the worksheet or matrix as you work on your lit review!

Four Examples of Student Writing

In the four examples below, only ONE shows a good example of synthesis: the fourth column, or  Student D . For a web accessible version, click the link below the image.

Long description of "Four Examples of Student Writing" for web accessibility

• Download a copy of the "Four Examples of Student Writing" chart

Click on the example to view the pdf.

From Jennifer Lim

• << Previous: 5. Critically Analyze and Evaluate
• Next: 7. Write a Literature Review >>
• Last Updated: Aug 12, 2024 11:48 AM
• URL: https://researchguides.uoregon.edu/litreview

Contact Us Library Accessibility UO Libraries Privacy Notices and Procedures

1501 Kincaid Street Eugene, OR 97403 P: 541-346-3053 F: 541-346-3485

• Visit us on Facebook
• Visit us on Twitter
• Visit us on Youtube
• Visit us on Instagram
• Report a Concern
• Nondiscrimination and Title IX
• Accessibility
• Privacy Policy
• Find People

Literature Syntheis 101

How To Synthesise The Existing Research (With Examples)

By: Derek Jansen (MBA) | Expert Reviewer: Eunice Rautenbach (DTech) | August 2023

One of the most common mistakes that students make when writing a literature review is that they err on the side of describing the existing literature rather than providing a critical synthesis of it. In this post, we’ll unpack what exactly synthesis means and show you how to craft a strong literature synthesis using practical examples.

This post is based on our popular online course, Literature Review Bootcamp . In the course, we walk you through the full process of developing a literature review, step by step. If it’s your first time writing a literature review, you definitely want to use this link to get 50% off the course (limited-time offer).

Overview: Literature Synthesis

• What exactly does “synthesis” mean?
• Aspect 1: Agreement
• Aspect 2: Disagreement
• Aspect 3: Key theories
• Aspect 4: Contexts
• Aspect 5: Methodologies
• Bringing it all together

What does “synthesis” actually mean?

As a starting point, let’s quickly define what exactly we mean when we use the term “synthesis” within the context of a literature review.

Simply put, literature synthesis means going beyond just describing what everyone has said and found. Instead, synthesis is about bringing together all the information from various sources to present a cohesive assessment of the current state of knowledge in relation to your study’s research aims and questions .

Put another way, a good synthesis tells the reader exactly where the current research is “at” in terms of the topic you’re interested in – specifically, what’s known , what’s not , and where there’s a need for more research .

So, how do you go about doing this?

Well, there’s no “one right way” when it comes to literature synthesis, but we’ve found that it’s particularly useful to ask yourself five key questions when you’re working on your literature review. Having done so,  you can then address them more articulately within your actual write up. So, let’s take a look at each of these questions.

1. Points Of Agreement

The first question that you need to ask yourself is: “Overall, what things seem to be agreed upon by the vast majority of the literature?”

For example, if your research aim is to identify which factors contribute toward job satisfaction, you’ll need to identify which factors are broadly agreed upon and “settled” within the literature. Naturally, there may at times be some lone contrarian that has a radical viewpoint , but, provided that the vast majority of researchers are in agreement, you can put these random outliers to the side. That is, of course, unless your research aims to explore a contrarian viewpoint and there’s a clear justification for doing so. 

Identifying what’s broadly agreed upon is an essential starting point for synthesising the literature, because you generally don’t want (or need) to reinvent the wheel or run down a road investigating something that is already well established . So, addressing this question first lays a foundation of “settled” knowledge.

Need a helping hand?

2. Points Of Disagreement

Related to the previous point, but on the other end of the spectrum, is the equally important question: “Where do the disagreements lie?” .

In other words, which things are not well agreed upon by current researchers? It’s important to clarify here that by disagreement, we don’t mean that researchers are (necessarily) fighting over it – just that there are relatively mixed findings within the empirical research , with no firm consensus amongst researchers.

This is a really important question to address as these “disagreements” will often set the stage for the research gap(s). In other words, they provide clues regarding potential opportunities for further research, which your study can then (hopefully) contribute toward filling. If you’re not familiar with the concept of a research gap, be sure to check out our explainer video covering exactly that .

3. Key Theories

The next question you need to ask yourself is: “Which key theories seem to be coming up repeatedly?” .

Within most research spaces, you’ll find that you keep running into a handful of key theories that are referred to over and over again. Apart from identifying these theories, you’ll also need to think about how they’re connected to each other. Specifically, you need to ask yourself:

• Are they all covering the same ground or do they have different focal points  or underlying assumptions ?
• Do some of them feed into each other and if so, is there an opportunity to integrate them into a more cohesive theory?
• Do some of them pull in different directions ? If so, why might this be?
• Do all of the theories define the key concepts and variables in the same way, or is there some disconnect? If so, what’s the impact of this ?

Simply put, you’ll need to pay careful attention to the key theories in your research area, as they will need to feature within your theoretical framework , which will form a critical component within your final literature review. This will set the foundation for your entire study, so it’s essential that you be critical in this area of your literature synthesis.

If this sounds a bit fluffy, don’t worry. We deep dive into the theoretical framework (as well as the conceptual framework) and look at practical examples in Literature Review Bootcamp . If you’d like to learn more, take advantage of our limited-time offer to get 60% off the standard price.

4. Contexts

The next question that you need to address in your literature synthesis is an important one, and that is: “Which contexts have (and have not) been covered by the existing research?” .

For example, sticking with our earlier hypothetical topic (factors that impact job satisfaction), you may find that most of the research has focused on white-collar , management-level staff within a primarily Western context, but little has been done on blue-collar workers in an Eastern context. Given the significant socio-cultural differences between these two groups, this is an important observation, as it could present a contextual research gap .

In practical terms, this means that you’ll need to carefully assess the context of each piece of literature that you’re engaging with, especially the empirical research (i.e., studies that have collected and analysed real-world data). Ideally, you should keep notes regarding the context of each study in some sort of catalogue or sheet, so that you can easily make sense of this before you start the writing phase. If you’d like, our free literature catalogue worksheet is a great tool for this task.

5. Methodological Approaches

Last but certainly not least, you need to ask yourself the question: “What types of research methodologies have (and haven’t) been used?”

For example, you might find that most studies have approached the topic using qualitative methods such as interviews and thematic analysis. Alternatively, you might find that most studies have used quantitative methods such as online surveys and statistical analysis.

But why does this matter?

Well, it can run in one of two potential directions . If you find that the vast majority of studies use a specific methodological approach, this could provide you with a firm foundation on which to base your own study’s methodology . In other words, you can use the methodologies of similar studies to inform (and justify) your own study’s research design .

On the other hand, you might argue that the lack of diverse methodological approaches presents a research gap , and therefore your study could contribute toward filling that gap by taking a different approach. For example, taking a qualitative approach to a research area that is typically approached quantitatively. Of course, if you’re going to go against the methodological grain, you’ll need to provide a strong justification for why your proposed approach makes sense. Nevertheless, it is something worth at least considering.

Regardless of which route you opt for, you need to pay careful attention to the methodologies used in the relevant studies and provide at least some discussion about this in your write-up. Again, it’s useful to keep track of this on some sort of spreadsheet or catalogue as you digest each article, so consider grabbing a copy of our free literature catalogue if you don’t have anything in place.

Bringing It All Together

Alright, so we’ve looked at five important questions that you need to ask (and answer) to help you develop a strong synthesis within your literature review.  To recap, these are:

• Which things are broadly agreed upon within the current research?
• Which things are the subject of disagreement (or at least, present mixed findings)?
• Which theories seem to be central to your research topic and how do they relate or compare to each other?
• Which contexts have (and haven’t) been covered?
• Which methodological approaches are most common?

Importantly, you’re not just asking yourself these questions for the sake of asking them – they’re not just a reflection exercise. You need to weave your answers to them into your actual literature review when you write it up. How exactly you do this will vary from project to project depending on the structure you opt for, but you’ll still need to address them within your literature review, whichever route you go.

The best approach is to spend some time actually writing out your answers to these questions, as opposed to just thinking about them in your head. Putting your thoughts onto paper really helps you flesh out your thinking . As you do this, don’t just write down the answers – instead, think about what they mean in terms of the research gap you’ll present , as well as the methodological approach you’ll take . Your literature synthesis needs to lay the groundwork for these two things, so it’s essential that you link all of it together in your mind, and of course, on paper.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

excellent , thank you

Thank you for this significant piece of information.

This piece of information is very helpful. Thank you so much and look forward to hearing more literature review from you in near the future.

Submit a Comment Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Print Friendly

How to Synthesize Written Information from Multiple Sources

Shona McCombes

Content Manager

B.A., English Literature, University of Glasgow

Shona McCombes is the content manager at Scribbr, Netherlands.

Learn about our Editorial Process

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.

On This Page:

When you write a literature review or essay, you have to go beyond just summarizing the articles you’ve read – you need to synthesize the literature to show how it all fits together (and how your own research fits in).

Synthesizing simply means combining. Instead of summarizing the main points of each source in turn, you put together the ideas and findings of multiple sources in order to make an overall point.

At the most basic level, this involves looking for similarities and differences between your sources. Your synthesis should show the reader where the sources overlap and where they diverge.

Unsynthesized Example

Franz (2008) studied undergraduate online students. He looked at 17 females and 18 males and found that none of them liked APA. According to Franz, the evidence suggested that all students are reluctant to learn citations style. Perez (2010) also studies undergraduate students. She looked at 42 females and 50 males and found that males were significantly more inclined to use citation software ( p < .05). Findings suggest that females might graduate sooner. Goldstein (2012) looked at British undergraduates. Among a sample of 50, all females, all confident in their abilities to cite and were eager to write their dissertations.

Synthesized Example

Studies of undergraduate students reveal conflicting conclusions regarding relationships between advanced scholarly study and citation efficacy. Although Franz (2008) found that no participants enjoyed learning citation style, Goldstein (2012) determined in a larger study that all participants watched felt comfortable citing sources, suggesting that variables among participant and control group populations must be examined more closely. Although Perez (2010) expanded on Franz’s original study with a larger, more diverse sample…

Step 1: Organize your sources

After collecting the relevant literature, you’ve got a lot of information to work through, and no clear idea of how it all fits together.

Before you can start writing, you need to organize your notes in a way that allows you to see the relationships between sources.

One way to begin synthesizing the literature is to put your notes into a table. Depending on your topic and the type of literature you’re dealing with, there are a couple of different ways you can organize this.

Summary table

A summary table collates the key points of each source under consistent headings. This is a good approach if your sources tend to have a similar structure – for instance, if they’re all empirical papers.

Each row in the table lists one source, and each column identifies a specific part of the source. You can decide which headings to include based on what’s most relevant to the literature you’re dealing with.

For example, you might include columns for things like aims, methods, variables, population, sample size, and conclusion.

For each study, you briefly summarize each of these aspects. You can also include columns for your own evaluation and analysis.

The summary table gives you a quick overview of the key points of each source. This allows you to group sources by relevant similarities, as well as noticing important differences or contradictions in their findings.

Synthesis matrix

A synthesis matrix is useful when your sources are more varied in their purpose and structure – for example, when you’re dealing with books and essays making various different arguments about a topic.

Each column in the table lists one source. Each row is labeled with a specific concept, topic or theme that recurs across all or most of the sources.

Then, for each source, you summarize the main points or arguments related to the theme.

The purposes of the table is to identify the common points that connect the sources, as well as identifying points where they diverge or disagree.

Step 2: Outline your structure

Now you should have a clear overview of the main connections and differences between the sources you’ve read. Next, you need to decide how you’ll group them together and the order in which you’ll discuss them.

For shorter papers, your outline can just identify the focus of each paragraph; for longer papers, you might want to divide it into sections with headings.

There are a few different approaches you can take to help you structure your synthesis.

If your sources cover a broad time period, and you found patterns in how researchers approached the topic over time, you can organize your discussion chronologically .

That doesn’t mean you just summarize each paper in chronological order; instead, you should group articles into time periods and identify what they have in common, as well as signalling important turning points or developments in the literature.

If the literature covers various different topics, you can organize it thematically .

That means that each paragraph or section focuses on a specific theme and explains how that theme is approached in the literature.

Source Used with Permission: The Chicago School

If you’re drawing on literature from various different fields or they use a wide variety of research methods, you can organize your sources methodologically .

That means grouping together studies based on the type of research they did and discussing the findings that emerged from each method.

If your topic involves a debate between different schools of thought, you can organize it theoretically .

That means comparing the different theories that have been developed and grouping together papers based on the position or perspective they take on the topic, as well as evaluating which arguments are most convincing.

Step 3: Write paragraphs with topic sentences

What sets a synthesis apart from a summary is that it combines various sources. The easiest way to think about this is that each paragraph should discuss a few different sources, and you should be able to condense the overall point of the paragraph into one sentence.

This is called a topic sentence , and it usually appears at the start of the paragraph. The topic sentence signals what the whole paragraph is about; every sentence in the paragraph should be clearly related to it.

A topic sentence can be a simple summary of the paragraph’s content:

“Early research on [x] focused heavily on [y].”

For an effective synthesis, you can use topic sentences to link back to the previous paragraph, highlighting a point of debate or critique:

“Several scholars have pointed out the flaws in this approach.” “While recent research has attempted to address the problem, many of these studies have methodological flaws that limit their validity.”

By using topic sentences, you can ensure that your paragraphs are coherent and clearly show the connections between the articles you are discussing.

As you write your paragraphs, avoid quoting directly from sources: use your own words to explain the commonalities and differences that you found in the literature.

Don’t try to cover every single point from every single source – the key to synthesizing is to extract the most important and relevant information and combine it to give your reader an overall picture of the state of knowledge on your topic.

Step 4: Revise, edit and proofread

Like any other piece of academic writing, synthesizing literature doesn’t happen all in one go – it involves redrafting, revising, editing and proofreading your work.

Checklist for Synthesis

•   Do I introduce the paragraph with a clear, focused topic sentence?
•   Do I discuss more than one source in the paragraph?
•   Do I mention only the most relevant findings, rather than describing every part of the studies?
•   Do I discuss the similarities or differences between the sources, rather than summarizing each source in turn?
•   Do I put the findings or arguments of the sources in my own words?
•   Is the paragraph organized around a single idea?
•   Is the paragraph directly relevant to my research question or topic?
•   Is there a logical transition from this paragraph to the next one?

Further Information

How to Synthesise: a Step-by-Step Approach

Help…I”ve Been Asked to Synthesize!

Learn how to Synthesise (combine information from sources)

How to write a Psychology Essay

Literature Synthesis: Guide To Synthesise & Write Literature Review

Literature synthesis is a crucial skill for researchers and scholars, allowing them to integrate findings from multiple sources into a coherent analysis. Mastering literature synthesis will enhance your research and writing skills. 

This guide will walk you through the process of synthesising and writing a literature review, providing practical steps and insider tips. Learn how to:

• organise your sources,
• identify key themes, and
• create a cohesive narrative that highlights both agreements and disagreements within the existing literature.

Literature Synthesis vs Literature Review

You may be familiar with literature review, and the term literature synthesis may throw you off a bit. Are they a similar thing, or something different from each other?

If you are still unsure about how literature synthesis is different from literature review, here are a couple of points to think about: 

Approach To Sources

One difference is the approach to sources. In a literature review, you might describe each source separately, detailing its findings and contributions.

With synthesis, you combine the ideas from multiple sources to highlight relationships and gaps.

One example would be you may find that several studies agree on a particular theme but use different methodologies to reach their conclusions.

Organisation

A second difference is the organization. Literature reviews typically follow a structured format, summarizing each source in a new paragraph.

In contrast, synthesis requires organising sources around key themes or topics. This might involve using a synthesis matrix to align findings and theories from different sources into a cohesive analysis.

How To Evaluate Literature

Evaluating the literature also differs. When you write a literature review, you summarise and describe the existing research. Synthesis goes further by:

• critically evaluating the sources,
• identifying points of agreement and disagreement, and
• assessing the overall state of knowledge.

You need to address the methodological approaches used and how they relate to your research questions.

In terms of purpose, a literature review provides an overview of what’s known about a topic. It sets the stage for your research by summarising existing knowledge.

Synthesis, meanwhile, aims to create new insights by combining and contrasting different sources. This process helps you identify research gaps and questions that need further investigation.

Writing Process

Finally, the writing process differs. A literature review involves compiling summaries, often following a step-by-step guide.

With synthesis, you need to integrate:

• theories, and
• methodologies from various sources.

This involves weaving together different perspectives into a single, cohesive narrative that supports your research aims.

How To Perform Literature Synthesis?

Performing literature synthesis can be daunting, but by breaking it down step by step, you can create a comprehensive and coherent analysis of your topic.

Here’s a guide to help you through the process, with insider details and practical examples that will make your task easier.

Organise Your Sources

First, you need to gather and organise your sources. Start by conducting a thorough search of the existing literature on your topic, using

• research guides,
• library databases, and
• academic journals to find relevant sources.

There are plenty of AI tools that can help with process as well – make sure you check out my guide on best AI tools for literature review.

Record the main points of each source in a summary table. This table should include columns for:

• the author,
• publication year,
• key points,
• methodologies used, and

By organising your sources in this way, you’ll have a clear overview of the existing literature.

Identify Themes

Once you have your sources organised, it’s time to start synthesising the literature. This means combining the ideas and findings from multiple sources to create a cohesive analysis.

Begin by identifying the key themes that emerge from your sources. These themes will form the basis of your synthesis.

Suppose you are you’re researching job satisfaction, In this case, you might find recurring themes such as work-life balance, salary, and workplace environment.

Create A Synthesis Matrix

Next, create a synthesis matrix. This tool helps you organize the key points from each source under the identified themes.

Each row in the matrix represents a source, and each column represents a theme.

By filling in the matrix, you can see how different sources relate to each theme. This will help you identify similarities and differences between the sources.

Write Your Literature Synthesis

With your synthesis matrix in hand, you can start writing your literature synthesis.

Begin each paragraph with a clear topic sentence that identifies the theme you’re discussing. Then, weave together the findings from different sources, highlighting points of agreement and disagreement.

One way you may write this include: “While Franz (2008) found that salary is a major factor in job satisfaction, Goldstein (2012) argued that work-life balance plays a more significant role.”

Critically Evaluate Your Sources

Be sure to critically evaluate the sources as you synthesize the literature. This means assessing the methodologies used in each study and considering their impact on the findings.

Let’s say you found that most studies on job satisfaction used qualitative methods , you might question whether the findings would differ if quantitative methods were used. Addressing these methodological differences can help you identify research gaps and areas for further study.

Don’t Just Summarise

As you write your paragraphs, avoid simply summarising each source. Instead, combine the key points from multiple sources to create a more comprehensive analysis.

If we reuse Franz (2008) as example, rather than describing Franz’s study in one paragraph and Goldstein’s study in another, integrate their findings to show how they relate to each other.

This approach will make your synthesis more cohesive and easier to follow.

Address The Broader Context Of The Topic

To create a strong synthesis, you also need to address the broader context of your research. This means considering the theoretical frameworks and empirical evidence that underpin your topic.

If you’re researching job satisfaction, you might discuss how different theories of motivation relate to your findings. By integrating these broader perspectives, you can provide a more comprehensive overview of the current state of knowledge.

Keep Questioning Yourself

Throughout the writing process, keep the five key questions in mind:

• What’s broadly agreed upon within the current research?
• Where do the disagreements lie?
• Which theories are central to your research topic?
• Which contexts have been covered, and which haven’t?
• What types of research methodologies have been used?

Addressing these questions will help you create a more thorough and insightful synthesis.

Revise & Edit

Finally, revise and edit your work. This means checking for clarity, coherence, and logical flow. Make sure each paragraph has a clear topic sentence and that all sentences within the paragraph relate to that topic.

Remove any unnecessary information and ensure that your synthesis is well-organised and easy to follow.

Your Guide To Synthesise Literature

Performing literature synthesis may seem overwhelming, but by following this step-by-step guide, you can create a comprehensive and cohesive analysis of your topic.

Use tools like summary tables and synthesis matrices to organise your sources, and focus on combining the key points from multiple sources to create a strong synthesis.

With careful planning and critical evaluation, you can produce a literature synthesis that provides valuable insights into your field of study.

Dr Andrew Stapleton has a Masters and PhD in Chemistry from the UK and Australia. He has many years of research experience and has worked as a Postdoctoral Fellow and Associate at a number of Universities. Although having secured funding for his own research, he left academia to help others with his YouTube channel all about the inner workings of academia and how to make it work for you.

Thank you for visiting Academia Insider.

We are here to help you navigate Academia as painlessly as possible. We are supported by our readers and by visiting you are helping us earn a small amount through ads and affiliate revenue - Thank you!

2024 © Academia Insider

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

Chapter 7: Synthesizing Sources

Learning objectives.

At the conclusion of this chapter, you will be able to:

• synthesize key sources connecting them with the research question and topic area.

7.1 Overview of synthesizing

7.1.1 putting the pieces together.

Combining separate elements into a whole is the dictionary definition of synthesis.  It is a way to make connections among and between numerous and varied source materials.  A literature review is not an annotated bibliography, organized by title, author, or date of publication.  Rather, it is grouped by topic to create a whole view of the literature relevant to your research question.

Your synthesis must demonstrate a critical analysis of the papers you collected as well as your ability to integrate the results of your analysis into your own literature review.  Each paper collected should be critically evaluated and weighed for “adequacy, appropriateness, and thoroughness” ( Garrard, 2017 ) before inclusion in your own review.  Papers that do not meet this criteria likely should not be included in your literature review.

Begin the synthesis process by creating a grid, table, or an outline where you will summarize, using common themes you have identified and the sources you have found. The summary grid or outline will help you compare and contrast the themes so you can see the relationships among them as well as areas where you may need to do more searching. Whichever method you choose, this type of organization will help you to both understand the information you find and structure the writing of your review.  Remember, although “the means of summarizing can vary, the key at this point is to make sure you understand what you’ve found and how it relates to your topic and research question” ( Bennard et al., 2014 ).

As you read through the material you gather, look for common themes as they may provide the structure for your literature review.  And, remember, research is an iterative process: it is not unusual to go back and search information sources for more material.

At one extreme, if you are claiming, ‘There are no prior publications on this topic,’ it is more likely that you have not found them yet and may need to broaden your search.  At another extreme, writing a complete literature review can be difficult with a well-trod topic.  Do not cite it all; instead cite what is most relevant.  If that still leaves too much to include, be sure to reference influential sources…as well as high-quality work that clearly connects to the points you make. ( Klingner, Scanlon, & Pressley, 2005 ).

7.2 Creating a summary table

Literature reviews can be organized sequentially or by topic, theme, method, results, theory, or argument.  It’s important to develop categories that are meaningful and relevant to your research question.  Take detailed notes on each article and use a consistent format for capturing all the information each article provides.  These notes and the summary table can be done manually, using note cards.  However, given the amount of information you will be recording, an electronic file created in a word processing or spreadsheet is more manageable. Examples of fields you may want to capture in your notes include:

• Authors’ names
• Article title
• Publication year
• Main purpose of the article
• Methodology or research design
• Participants
• Measurement
• Conclusions

  Other fields that will be useful when you begin to synthesize the sum total of your research:

• Specific details of the article or research that are especially relevant to your study
• Key terms and definitions
• Strengths or weaknesses in research design
• Relationships to other studies
• Possible gaps in the research or literature (for example, many research articles conclude with the statement “more research is needed in this area”)
• Finally, note how closely each article relates to your topic.  You may want to rank these as high, medium, or low relevance.  For papers that you decide not to include, you may want to note your reasoning for exclusion, such as ‘small sample size’, ‘local case study,’ or ‘lacks evidence to support assertion.’

This short video demonstrates how a nursing researcher might create a summary table.

7.2.1 Creating a Summary Table

  Summary tables can be organized by author or by theme, for example:

For a summary table template, see http://blogs.monm.edu/writingatmc/files/2013/04/Synthesis-Matrix-Template.pdf

7.3 Creating a summary outline

An alternate way to organize your articles for synthesis it to create an outline. After you have collected the articles you intend to use (and have put aside the ones you won’t be using), it’s time to identify the conclusions that can be drawn from the articles as a group.

  Based on your review of the collected articles, group them by categories.  You may wish to further organize them by topic and then chronologically or alphabetically by author.  For each topic or subtopic you identified during your critical analysis of the paper, determine what those papers have in common.  Likewise, determine which ones in the group differ.  If there are contradictory findings, you may be able to identify methodological or theoretical differences that could account for the contradiction (for example, differences in population demographics).  Determine what general conclusions you can report about the topic or subtopic as the entire group of studies relate to it.  For example, you may have several studies that agree on outcome, such as ‘hands on learning is best for science in elementary school’ or that ‘continuing education is the best method for updating nursing certification.’ In that case, you may want to organize by methodology used in the studies rather than by outcome.

Organize your outline in a logical order and prepare to write the first draft of your literature review.  That order might be from broad to more specific, or it may be sequential or chronological, going from foundational literature to more current.  Remember, “an effective literature review need not denote the entire historical record, but rather establish the raison d’etre for the current study and in doing so cite that literature distinctly pertinent for theoretical, methodological, or empirical reasons.” ( Milardo, 2015, p. 22 ).

As you organize the summarized documents into a logical structure, you are also appraising and synthesizing complex information from multiple sources.  Your literature review is the result of your research that synthesizes new and old information and creates new knowledge.

7.4 Additional resources:

Literature Reviews: Using a Matrix to Organize Research / Saint Mary’s University of Minnesota

Literature Review: Synthesizing Multiple Sources / Indiana University

Writing a Literature Review and Using a Synthesis Matrix / Florida International University

 Sample Literature Reviews Grid / Complied by Lindsay Roberts

Select three or four articles on a single topic of interest to you. Then enter them into an outline or table in the categories you feel are important to a research question. Try both the grid and the outline if you can to see which suits you better. The attached grid contains the fields suggested in the video .

Literature Review Table  

Test Yourself

• Select two articles from your own summary table or outline and write a paragraph explaining how and why the sources relate to each other and your review of the literature.
• In your literature review, under what topic or subtopic will you place the paragraph you just wrote?

Image attribution

Literature Reviews for Education and Nursing Graduate Students Copyright © by Linda Frederiksen is licensed under a Creative Commons Attribution 4.0 International License , except where otherwise noted.

Share This Book

How to Write a Literature Review - A Self-Guided Tutorial

• Literature Reviews: A Recap
• Reading Journal Articles
• Does it describe a Literature Review?
• 1. Identify the question
• 2. Review discipline styles
• Searching article databases - video
• Finding the article full-text
• Citation trails
• When to stop searching
• Citation Managers
• 5. Critically analyze and evaluate
• 6. Synthesize
• 7. Write literature review
• Additional Resources

You can meet with a librarian to talk about your literature review, or other library-related topics.

You can sort the literature in various ways, for example:

Synthesis Vizualization

Four examples of student writing.

In the four examples below, only ONE shows a good example of synthesis: the fourth column, or  Student D . For a web accessible version, click the link below the image.

Long description of "Four Examples of Student Writing" for web accessibility

• Download a copy of the "Four Examples of Student Writing" chart

Synthesis Matrix Example

From Jennifer Lim

Synthesis Templates

Synthesis grids are organizational tools used to record the main concepts of your sources and can help you make connections about how your sources relate to one another.

• Source Template Basic Literature Review Source Template from Walden University Writing Center to help record the main findings and concepts from different articles.
• Sample Literature Review Grids This spreadsheet contains multiple tabs with different grid templates. Download or create your own copy to begin recording notes.
• << Previous: 5. Critically analyze and evaluate
• Next: 7. Write literature review >>
• Last Updated: Sep 17, 2024 12:56 PM
• URL: https://libguides.ucmerced.edu/literature-review

Library Guides

Literature reviews: synthesis.

• Criticality

Synthesise Information

So, how can you create paragraphs within your literature review that demonstrates your knowledge of the scholarship that has been done in your field of study?  

You will need to present a synthesis of the texts you read.  

Doug Specht, Senior Lecturer at the Westminster School of Media and Communication, explains synthesis for us in the following video:  

Synthesising Texts  

What is synthesis? 

Synthesis is an important element of academic writing, demonstrating comprehension, analysis, evaluation and original creation.  

With synthesis you extract content from different sources to create an original text. While paraphrase and summary maintain the structure of the given source(s), with synthesis you create a new structure.  

The sources will provide different perspectives and evidence on a topic. They will be put together when agreeing, contrasted when disagreeing. The sources must be referenced.  

Perfect your synthesis by showing the flow of your reasoning, expressing critical evaluation of the sources and drawing conclusions.  

When you synthesise think of "using strategic thinking to resolve a problem requiring the integration of diverse pieces of information around a structuring theme" (Mateos and Sole 2009, p448). 

Synthesis is a complex activity, which requires a high degree of comprehension and active engagement with the subject. As you progress in higher education, so increase the expectations on your abilities to synthesise. 

How to synthesise in a literature review: 

Identify themes/issues you'd like to discuss in the literature review. Think of an outline.  

Read the literature and identify these themes/issues.  

Critically analyse the texts asking: how does the text I'm reading relate to the other texts I've read on the same topic? Is it in agreement? Does it differ in its perspective? Is it stronger or weaker? How does it differ (could be scope, methods, year of publication etc.). Draw your conclusions on the state of the literature on the topic.  

Start writing your literature review, structuring it according to the outline you planned.  

Put together sources stating the same point; contrast sources presenting counter-arguments or different points.  

Present your critical analysis.  

Always provide the references. 

The best synthesis requires a "recursive process" whereby you read the source texts, identify relevant parts, take notes, produce drafts, re-read the source texts, revise your text, re-write... (Mateos and Sole, 2009). 

What is good synthesis?  

The quality of your synthesis can be assessed considering the following (Mateos and Sole, 2009, p439):  

Integration and connection of the information from the source texts around a structuring theme. 

Selection of ideas necessary for producing the synthesis. 

Appropriateness of the interpretation.  

Elaboration of the content.  

Example of Synthesis

Original texts (fictitious): 

Synthesis: 

Animal experimentation is a subject of heated debate. Some argue that painful experiments should be banned. Indeed it has been demonstrated that such experiments make animals suffer physically and psychologically (Chowdhury 2012; Panatta and Hudson 2016). On the other hand, it has been argued that animal experimentation can save human lives and reduce harm on humans (Smith 2008). This argument is only valid for toxicological testing, not for tests that, for example, merely improve the efficacy of a cosmetic (Turner 2015). It can be suggested that animal experimentation should be regulated to only allow toxicological risk assessment, and the suffering to the animals should be minimised.   

Bibliography

Mateos, M. and Sole, I. (2009). Synthesising Information from various texts: A Study of Procedures and Products at Different Educational Levels. European Journal of Psychology of Education,  24 (4), 435-451. Available from https://doi.org/10.1007/BF03178760 [Accessed 29 June 2021].

• << Previous: Structure
• Next: Criticality >>
• Last Updated: Nov 18, 2023 10:56 PM
• URL: https://libguides.westminster.ac.uk/literature-reviews

CONNECT WITH US

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

Writing a Literature Review

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

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.

Literature Reviews

• 5. Synthesize your findings
• Getting started
• Types of reviews
• 1. Define your research question
• 2. Plan your search
• 3. Search the literature
• 4. Organize your results

How to synthesize

Approaches to synthesis.

• 6. Write the review
• Artificial intelligence (AI) tools
• Thompson Writing Studio This link opens in a new window
• Need to write a systematic review? This link opens in a new window

Contact a Librarian

Ask a Librarian

In the synthesis step of a literature review, researchers analyze and integrate information from selected sources to identify patterns and themes. This involves critically evaluating findings, recognizing commonalities, and constructing a cohesive narrative that contributes to the understanding of the research topic.

Here are some examples of how to approach synthesizing the literature:

💡 By themes or concepts

🕘 Historically or chronologically

📊 By methodology

These organizational approaches can also be used when writing your review. It can be beneficial to begin organizing your references by these approaches in your citation manager by using folders, groups, or collections.

Create a synthesis matrix

A synthesis matrix allows you to visually organize your literature.

Topic: ______________________________________________

Topic: Chemical exposure to workers in nail salons

• << Previous: 4. Organize your results
• Next: 6. Write the review >>
• Last Updated: Sep 17, 2024 1:24 PM
• URL: https://guides.library.duke.edu/litreviews

Services for...

• Faculty & Instructors
• Graduate Students
• Undergraduate Students
• International Students
• Patrons with Disabilities

• Harmful Language Statement
• Re-use & Attribution / Privacy
• Support the Libraries

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, generate accurate citations for free.

• Knowledge Base

Methodology

• 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.

Instantly correct all language mistakes in your text

Upload your document to correct all your mistakes in minutes

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.

Prevent plagiarism. Run a free check.

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.

Don't submit your assignments before you do this

The academic proofreading tool has been trained on 1000s of academic texts. Making it the most accurate and reliable proofreading tool for students. Free citation check included.

Try for free

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.

Open Google Slides Download PowerPoint

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 .  

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

McCombes, S. (2023, September 11). How to Write a Literature Review | Guide, Examples, & Templates. Scribbr. Retrieved September 23, 2024, from https://www.scribbr.com/dissertation/literature-review/

Is this article helpful?

Shona McCombes

Other students also liked, what is a theoretical framework | guide to organizing, what is a research methodology | steps & tips, how to write a research proposal | examples & templates, what is your plagiarism score.

• Research Guides

Literature Review: A Self-Guided Tutorial

Using a synthesis matrix.

• Literature Reviews: A Recap
• Peer Review
• Reading the Literature
• Using Concept Maps
• Developing Research Questions
• Considering Strong Opinions
• 2. Review discipline styles
• Super Searching
• Finding the Full Text
• Citation Searching This link opens in a new window
• When to stop searching
• Citation Management
• Annotating Articles Tip
• 5. Critically analyze and evaluate
• How to Review the Literature
• 7. Write literature review

A synthesis matrix visually represents your research by organizing your sources by themes:

• Sample Synthesis Matrix Example provided by Ashford University Writing Center .
• << Previous: How to Review the Literature
• Next: 7. Write literature review >>
• Last Updated: Jul 30, 2024 4:12 PM
• URL: https://libguides.williams.edu/literature-review

Literature Review How To

• Things To Consider
• Synthesizing Sources
• Video Tutorials
• Books On Literature Reviews

What is Synthesis

What is Synthesis? Synthesis writing is a form of analysis related to comparison and contrast, classification and division. On a basic level, synthesis requires the writer to pull together two or more summaries, looking for themes in each text. In synthesis, you search for the links between various materials in order to make your point. Most advanced academic writing, including literature reviews, relies heavily on synthesis. (Temple University Writing Center)  

How To Synthesize Sources in a Literature Review

Literature reviews synthesize large amounts of information and present it in a coherent, organized fashion. In a literature review you will be combining material from several texts to create a new text – your literature review.

You will use common points among the sources you have gathered to help you synthesize the material. This will help ensure that your literature review is organized by subtopic, not by source. This means various authors' names can appear and reappear throughout the literature review, and each paragraph will mention several different authors. 

When you shift from writing summaries of the content of a source to synthesizing content from sources, there is a number things you must keep in mind: 

• Look for specific connections and or links between your sources and how those relate to your thesis or question.
• When writing and organizing your literature review be aware that your readers need to understand how and why the information from the different sources overlap.
• Organize your literature review by the themes you find within your sources or themes you have identified. 
• << Previous: Things To Consider
• Next: Video Tutorials >>
• Last Updated: Nov 30, 2018 4:51 PM
• URL: https://libguides.csun.edu/literature-review

Report ADA Problems with Library Services and Resources

Welcome to the new OASIS website! We have academic skills, library skills, math and statistics support, and writing resources all together in one new home.

• Walden University
• Faculty Portal

Common Assignments: Synthesizing Your Sources

Synthesizing your sources.

To demonstrate your knowledge on a field through a review of literature, the key component is synthesis. To synthesize is to combine independent elements and form a cohesive whole; in essence, your literature review should integrate your sources and

• Identify patterns
• Critically discuss strengths and weaknesses of sources or the field
• Compare and contrast methods, approaches, and findings of authors
• Evaluate and interpret what is known in your field and what, if anything, is missing

A Metaphor for Synthesis

Imagine you are at a dinner party with other researchers and theorists from your field. Everyone is sitting around the table and discussing the state of your field of research. The beginning portion of your literature review would be similar to those dinner party guests who started the conversation by discussing foundational research and theories. The body of your literature review could take many forms: What guests are agreeing, and which are arguing? What are the debatable issues, and are there any subtopics of those key topics? Does one particular guest keep interrupting the table's conversation? The final portion of your literature review would be similar to the host of the dinner party ending the debate with a comprehensive speech that touches on all opinions yet provides closure for the conversation.

Local and Global Synthesis

When writers synthesize successfully, they present new ideas based on interpretations of other evidence or arguments. In a literature review, it can helpful to think about synthesis occurring at both the local (or paragraph) level and the global (or section/paper) level.

Local Synthesis

Local synthesis occurs at the paragraph level when writers connect individual pieces of evidence from multiple sources to support a paragraph’s main idea and advance a paper’s thesis statement. A common example in academic writing is a scholarly paragraph that includes a main idea, evidence from multiple sources, and analysis of those multiple sources together.

Example: Based on the metaphor above, local synthesis would occur during each individual conversation item. So, if you brought up a single issue within your topic, and several prominent scholars agree, while others disagree, you would represent this debate of a singular issue in that paragraph.

Global Synthesis

Global synthesis occurs at the paper (or, sometimes, section) level when writers connect ideas across paragraphs or sections to create a new narrative whole. In a literature review, which can either stand alone or be a section/chapter within a capstone, global synthesis in integral for cohesion and flow.

Example: Using the same dinner party metaphor, global synthesis occurs when a writer take a birds-eye view of the entire dinner party. What major topics were discussed and how were they linked to other ideas or conversations? What dinner party guests contributed to what ideas? And, finally, where did the guests leave the conversation at the end of the night? A summary of your dinner party, with its multiple guests and discussions, is what ultimately will bring order to major themes within your larger topic.

Tips for creating global synthesis within a literature review:

• Quick Tip: Create a heading outline to think through which headings should be placed where.
• Use topic sentences for each paragraph that clearly link ideas between paragraphs.
• Incorporate appropriate transitions throughout your draft to clearly connect ideas.

Related Resources

Didn't find what you need? Email us at [email protected] .

• Previous Page: Literature Reviews
• Next Page: Commentary Versus Opinion
• Office of Student Disability Services

Walden Resources

Departments.

• Academic Residencies
• Academic Skills
• Career Planning and Development
• Customer Care Team
• Field Experience
• Military Services
• Student Success Advising
• Writing Skills

Centers and Offices

• Center for Social Change
• Office of Academic Support and Instructional Services
• Office of Degree Acceleration
• Office of Research and Doctoral Services
• Office of Student Affairs

Student Resources

• Doctoral Writing Assessment
• Form & Style Review
• Quick Answers
• ScholarWorks
• SKIL Courses and Workshops
• Walden Bookstore
• Walden Catalog & Student Handbook
• Student Safety/Title IX
• Legal & Consumer Information
• Website Terms and Conditions
• Cookie Policy
• Accessibility
• Accreditation
• State Authorization
• Net Price Calculator
• Cost of Attendance
• Contact Walden

Walden University is a member of Adtalem Global Education, Inc. www.adtalem.com Walden University is certified to operate by SCHEV © 2024 Walden University LLC. All rights reserved.

Writing the Literature Review

• Getting Started
• Step 1: Choose A Topic
• Step 2: Find Information
• Step 3: Evaluate
• Step 4: Take Notes
• Step 5: Synthesize
• Step 6: Stay Organized
• Write the Review

Synthesizing

What is "Synthesis"?

Synthesis?  

Synthesis refers to combining separate elements to create a whole.  When reading through your sources (peer reviewed journal articles, books, research studies, white papers etc.) you will pay attention to relationships between the studies, between groups in the studies, and look for any pattterns,  similarities or differences.  Pay attention to methodologies, unexplored themes, and things that may represent a "gap" in the literature.  These "gaps" will be things you will want to be sure to identify in your literature review.  

• Using a Synthesis Matrix to Plan a Literature Review Introduction to synthesis matrices, and explanation of the difference between synthesis and analysis. (Geared towards Health Science/ Nursing but applicable for other literature reviews) ***Includes a synthesis matrix example***
• Using a Spider Diagram Organize your thoughts with a spider diagram

Ready, Set...Synthesize

• Create an outline that puts your topics (and subtopics) into a logical order
• Look at each subtopic that you have identified and determine what the articles in that group have in common with each other
• Look at the articles in those subtopics that you have identified and look for areas where they differ.
• If you spot findings that are contradictory, what differences do you think could account for those contradictions?  
• Determine what general conclusions can be reported about that subtopic, and how it relates to the group of studies that you are discussing
• As you write, remember to follow your outline, and use transitions as you move between topics 

Galvan, J. L. (2006). Writing literature reviews (3rd ed.). Glendale, CA: Pyrczak Publishing

• << Previous: Step 4: Take Notes
• Next: Step 6: Stay Organized >>
• Last Updated: Sep 27, 2023 11:22 AM
• URL: https://guides.mga.edu/TheLiteratureReviewANDYou

478-471-2709 for the Macon campus library | 478-934-3179 for the Roberts Memorial Library at the Cochran campus | 478-275-6772 for the Dublin campus library

478-374-6833 for the Eastman campus library | 478-929-6804 for the Warner Robins campus library | On the Go? Text-A-Librarian: 478-285-4898

Middle Georgia State University Library

Book an Appointment With a Librarian

Literature Review Basics

• What is a Literature Review?
• Synthesizing Research
• Using Research & Synthesis Tables
• Additional Resources

Synthesis: What is it?

First, let's be perfectly clear about what synthesizing your research isn't :

• - It isn't  just summarizing the material you read
• - It isn't  generating a collection of annotations or comments (like an annotated bibliography)
• - It isn't  compiling a report on every single thing ever written in relation to your topic

When you  synthesize  your research, your job is to help your reader understand the current state of the conversation on your topic, relative to your research question.  That may include doing the following:

• - Selecting and using representative work on the topic
• - Identifying and discussing trends in published data or results
• - Identifying and explaining the impact of common features (study populations, interventions, etc.) that appear frequently in the literature
• - Explaining controversies, disputes, or central issues in the literature that are relevant to your research question
• - Identifying gaps in the literature, where more research is needed
• - Establishing the discussion to which your own research contributes and demonstrating the value of your contribution

Essentially, you're telling your reader where they are (and where you are) in the scholarly conversation about your project.

Synthesis: How do I do it?

Synthesis, step by step.

This is what you need to do  before  you write your review.

• Identify and clearly describe your research question (you may find the Formulating PICOT Questions table at  the Additional Resources tab helpful).
• Collect sources relevant to your research question.
• Organize and describe the sources you've found -- your job is to identify what  types  of sources you've collected (reviews, clinical trials, etc.), identify their  purpose  (what are they measuring, testing, or trying to discover?), determine the  level of evidence  they represent (see the Levels of Evidence table at the Additional Resources tab ), and briefly explain their  major findings . Use a Research Table to document this step.
• Study the information you've put in your Research Table and examine your collected sources, looking for  similarities  and  differences . Pay particular attention to  populations ,   methods  (especially relative to levels of evidence), and  findings .
• Analyze what you learn in (4) using a tool like a Synthesis Table. Your goal is to identify relevant themes, trends, gaps, and issues in the research.  Your literature review will collect the results of this analysis and explain them in relation to your research question.

Analysis tips

• - Sometimes, what you  don't  find in the literature is as important as what you do find -- look for questions that the existing research hasn't answered yet.
• - If any of the sources you've collected refer to or respond to each other, keep an eye on how they're related -- it may provide a clue as to whether or not study results have been successfully replicated.
• - Sorting your collected sources by level of evidence can provide valuable insight into how a particular topic has been covered, and it may help you to identify gaps worth addressing in your own work.
• << Previous: What is a Literature Review?
• Next: Using Research & Synthesis Tables >>
• Last Updated: Sep 26, 2023 12:06 PM
• URL: https://usi.libguides.com/literature-review-basics

SOC 200 - Sims: How to Write a Lit Review

• What are Literature Reviews?
• How to Write a Lit Review
• How to Choose a Topic
• Finding the Literature

How to write a literature review

Below are the steps you should follow when crafting a lit review for your class assignment.

• It's preferable if you can select a topic that you find interesting, because this will make the work seem less like work. 
• It's also important to select a topic that many researchers have already explored. This way, you'll actually have "literature" to "review."
• Sometimes, doing a very general search and reading other literature reviews can reveal a topic or avenue of research to you. 
• It's important to gain an understanding of your topic's research history, in order to properly comprehend how and why the current (emerging) research exists.
• One trick is to look at the References (aka Bibliographies aka Works Cited pages) of any especially relevant articles, in order to expand your search for those same sources. This is because there is often overlap between works, and if you're paying attention, one source can point you to several others.
• One method is to start with the most recently-published research and then use their citations to identify older research, allowing you to piece together a timeline and work backwards. 
• Chronologically : discuss the literature in order of its writing/publication. This will demonstrate a change in trends over time, and/or detail a history of controversy in the field, and/or illustrate developments in the field.
• Thematically : group your sources by subject or theme. This will show the variety of angels from which your topic has been studied. This method works well if you are trying to identify a sub-topic that has so far been overlooked by other researchers.
• Methodologically : group your sources by methodology. For example, divide the literature into categories like qualitative versus quantitative, or by population or geographical region, etc. 
• Theoretically : group your sources by theoretical lens. Your textbook should have a section(s) dedicated to the various theories in your field. If you're unsure, you should ask your professor.
• Are there disagreements on some issues, and consensus on others?
• How does this impact the path of research and discovery?
• Many articles will have a Limitations section, or a Discussion section, wherein suggestions are provided for next steps to further the research.
• These are goldmines for helping you see a possible outlook of the situation. 
• Identifying any gaps in the literature that are of a particular interest to your research goals will help you justify why your own research should be performed. 
• Be selective about which points from the source you use. The information should be the most important and the most relevant. 
• Use direct quotes sparingly, and don't rely too heavily on summaries and paraphrasing. You should be drawing conclusions about how the literature relates to your own analysis or the other literature. 
• Synthesize your sources. The goal is not to make a list of summaries, but to show how the sources relate to one another and to your own analysis. 
• At the end, make suggestions for future research. What subjects, populations, methodologies, or theoretical lenses warrant further exploration? What common flaws or biases did you identify that could be corrected in future studies? 
• Common citation styles for sociology classes include APA and ASA.

Understanding how a literature review is structured will help you as you craft your own. 

Below is information and example articles that you should review, in order to comprehend why they are written a certain way.

Below are some very good examples of Literature Reviews:

Cyberbullying: How Physical Intimidation Influences the Way People are Bullied

Use of Propofol and Emergence Agitation in Children

Eternity and Immortality in Spinoza's 'Ethics'

As you read these, take note of the sections that comprise the main structure of each one:

• Introduction 
• Summarize sources
• Synthesize sources

Below are some articles that provide very good examples of an "Introduction" section, which includes a "Review of the Literature."

• Sometimes, there is both an Introduction section, and a separate Review of the Literature section (oftentimes, it simply depends on the publication)

Krimm, H., & Lund, E. (2021). Efficacy of online learning modules for teaching dialogic reading strategies and phonemic awareness.  Language, Speech & Hearing Services in Schools,  52 (4), 1020-1030.  https://doi.org/10.1044/2021_LSHSS-21-00011

Melfsen, S., Jans, T., Romanos, M., & Walitza, S. (2022). Emotion regulation in selective mutism: A comparison group study in children and adolescents with selective mutism.  Journal of Psychiatric Research,  151 , 710-715.  https://doi.org/10.1016/j.jpsychires.2022.05.040

Citation Resources

• MU Library's Citing Sources page
• Purdue OWL's APA Guide
• APA Citation Style - Quick Guide
• Purdue OWL's ASA Guide
• ASA Citation Style - Quick Tips

Suggested Reading

• How to: Conduct a Lit Review (from Central Michigan University)
• Purdue OWL Writing Lab's Advice for Writing a Lit Review

How to Read a Scholarly Article

 read:.

• Things to consider when reading a scholarly article This helpful guide, from Meriam Library at California State University in Chico, explains what a scholarly article is and provides tips for reading them.

  Watch:

• How to read a scholarly article (YouTube) This tutorial, from Western University, quickly and efficiently describes how to read a scholarly article.
• << Previous: What are Literature Reviews?
• Next: How to Choose a Topic >>
• Last Updated: Sep 25, 2024 2:23 PM
• URL: https://libguides.marshall.edu/soc200-sims

Write a Literature Review

• Find This link opens in a new window

Get Organized

• Lit Review Prep Use this template to help you evaluate your sources, create article summaries for an annotated bibliography, and a synthesis matrix for your lit review outline.

Synthesize your Information

Synthesize: combine separate elements to form a whole.

Synthesis Matrix

A synthesis matrix helps you record the main points of each source and document how sources relate to each other.  After summarizing and evaluating your sources, arrange them in a matrix to help you see how they relate to each other, and apply to each of your themes or variables.  By arranging your sources in a matrix by theme or variable, you can see how your sources relate to each other, and can start thinking about how you weave them together to create a narrative.

• Step-by-Step Approach
• Example Matrix from NSCU
• Matrix Template
• << Previous: Summarize
• Next: Integrate >>
• Last Updated: Oct 11, 2023 12:20 PM
• URL: https://libraryguides.goucher.edu/literature-review

Conduct a literature review

• Introduction
• Identify the right articles
• Uncover related articles
• Read, summarize & synthesize
• Put it all together

Questions? Ask Me!

Read and summarize

Now it's time to read and evaluate each of the articles you found in your research. 

If you find an article isn't relevant or helpful, you can exclude it from your review. However, make sure that you don't exclude an article just because its findings don't match with other articles. Remember that part of a literature review is to point out inconsistencies! 

Take notes as you read! 

Make note of common themes you encounter in your readings. You might even want to create an annotated bibliography. You won't turn this in, but it will serve as a useful summary for you when you go to write the actual review. 

A useful tool for writing literature reviews is to create a  synthesis matrix . Each row represents a common theme or point; each column represents an article you read. 

The table below is a sample matrix created by Becky Menendez .

Things to note:

• The authors' names are listed across the top row
• The subtopics are listed across the left-most column
• Include some quotations, but for the most part, paraphrase or summarize
• Include page numbers for direct quotations in case you need to refer back to them

• << Previous: Uncover related articles
• Next: Put it all together >>
• Last Updated: Dec 15, 2023 9:48 AM
• URL: https://libraryguides.oswego.edu/how-to/conduct-lit-review

Click through the PLOS taxonomy to find articles in your field.

For more information about PLOS Subject Areas, click here .

Loading metrics

Open Access

Study Protocol

Exploring barriers and facilitators, and their effectiveness in eye health promotion interventions: Protocol of a systematic review

Roles Conceptualization, Methodology, Writing – original draft, Writing – review & editing

* E-mail: [email protected]

Affiliation Department of Public Health Medicine, School of Nursing and Public Health, University of KwaZulu-Natal, Durban, South Africa

Roles Conceptualization, Methodology, Writing – review & editing

Roles Methodology, Supervision, Writing – review & editing

Affiliation Department of Optometry, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa

• Hlabje Carel Masemola, 
• Sphamandla Josias Nkambule, 
• Olivia Baloyi, 
• Zamadonda Nokuthula Xulu-Kasaba

• Published: September 26, 2024
• https://doi.org/10.1371/journal.pone.0305904
• Reader Comments

The rising global prevalence of visual impairment attributed to population growth and ageing heightens the risk of increased vision problems for many. However, there is a limited understanding of factors influencing intervention implementation, and the degree to which participation is achieved in interventions for eye health promotion by eye care professionals is currently limited.

The purpose of this protocol is to review evidence on barriers and facilitators in eye health promotion, and their effectiveness on interventions employed in eye health promotion.

Methods and expected outputs

The Center for Reviews and Dissemination (CRD) guidance for conducting systematic reviews in healthcare and reporting in accordance with the PRISMA statement will serve as the basis for the implementation of the proposed systematic review. Systematic literature searches will be performed by searching three databases, as well as hand-searching articles eligible for inclusion. The searches will include peer-reviewed articles presenting evidence on eye health promotion intervention from the inception of the Vision 2020 Campaign to the present day. RevMan 5.3 software will be used to gather quantitative data, such as (Effectiveness), meta-analysis of such data will be performed. Two reviewers will conduct a quality appraisal of the included articles using the mixed methods appraisal tool (MMAT) 2018 version. We expect to find relevant studies on health promotion interventions among health professionals at different levels of care. The synthesized evidence will help guide further implementation of research on health promotion interventions for eye health.

Citation: Masemola HC, Nkambule SJ, Baloyi O, Xulu-Kasaba ZN (2024) Exploring barriers and facilitators, and their effectiveness in eye health promotion interventions: Protocol of a systematic review. PLoS ONE 19(9): e0305904. https://doi.org/10.1371/journal.pone.0305904

Editor: Adedayo Ajidahun, University of the Witwatersrand Johannesburg, SOUTH AFRICA

Received: February 1, 2024; Accepted: June 6, 2024; Published: September 26, 2024

Copyright: © 2024 Masemola et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: No datasets were generated or analysed during the current study as it is a protocol.

Funding: The author(s) received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist.

1. Background

Health promotion refers to interventions that are intended to improve population health and prevent illness [ 1 ]. Health promotion interventions are based on a variety of theories and models, including the socio-ecological model and the Health Belief Model. These models and theories focus on individual behaviours, community surroundings, and social structures [ 2 ]. These interventions aim to promote healthier lives, lower health risks, and address disparities through a variety of strategies, such as health education, policy changes, and community mobilization [ 3 ]. The literature presents evidence that health promotion interventions are effective in promoting positive health outcomes across a spectrum of health issues, such as infectious infections, mental health conditions, and chronic diseases [ 4 , 5 ]. Furthermore, to design and implement interventions that are responsive to the needs and living conditions of diverse populations and ultimately improve population health and well-being, the field emphasizes the significance of taking a holistic approach that takes into account social determinants of health, cultural contexts, and equity principles [ 6 , 7 ].

Enabling people and communities to take more control over their health and its determinants is crucial for health promotion, as defined by the Ottawa Charter for Health Promotion which contributes to achieving a state of optimal well-being [ 7 ]. The Ottawa Charter, which is based on the principles of empowerment, equity, and community involvement, offers a framework for holistically tackling health-related issues, including those of the promotion of eye health [ 8 ]. The Ottawa Charter’s action areas can be used to categorize interventions meant to improve eye health, including building healthy public policy, creating supportive environments, strengthening community action, developing personal skills, and reorienting health services [ 6 ]. Alignment of eye health promotion interventions with these action areas, this study seeks not only to review the nature and effectiveness of existing interventions but also to propose integrated strategies that address the needs of individuals at the community level.

Promoting eye health is an essential component of public health initiatives aimed to reduce the impact of vision impairment and improve overall community well-being [ 9 , 10 ]. Major global public health issues include loss of vision and age-related eye conditions [ 11 ]. In addition to reducing an individual’s quality of life, vision impairment poses major economic and social challenges for communities [ 12 ]. Globally, at least 2.2 billion people have vision impairment, whereas at least 1 billion could have been prevented through health promotion actions [ 9 ]. In recent evidence, an improvement of 61% to 70% was observed in the uptake of eye care services following public ocular health campaigns as one of their eye care interventions [ 13 ]. In developing effective health interventions, it has become imperative for health professionals to play a crucial role in their execution and implementation [ 14 ]. This is because health professionals are responsible for the improvement of access and provision of quality health care to a target population [ 14 ]. Similarly, eye care professionals such as optometrists have been reported to provide health care services based on one of the core principles of the Ottawa Charter which is a global health milestone on health promotion; reorientation of services in the form of identification, evaluation, and prevention of disease and disorders [ 15 ]. Health promotion services, rehabilitation services, and health system management services also fall within these core principles [ 15 ]. Sithole(2022), affirms eye health promotion as an integral part of any action plan that seeks to address causative factors of various forms of visual impairment and blindness [ 16 ]. Primary healthcare services are excellent entry points for providing these interventions that promote health and reduce the risk of visual impairment [ 17 ]. Primary health care enables health systems to address the individuals’ health requirements, from health promotion to disease prevention, treatment, rehabilitation, palliative care, and more, as more people seek health care services, such as eye care [ 17 ]. This approach also guarantees that the delivery of healthcare is centred on patients’ needs and respects their preferences [ 18 ]. Effective health treatments have proved beneficial in preventing non-communicable diseases, which may be attributed to how they are delivered in different healthcare settings [ 19 , 20 ]. When addressing these contexts, including implementation challenges and facilitators, it might be important to understand the techniques that improve the implementation of health-promoting interventions in various healthcare settings. According to the social-ecological model which focuses on multiple factors that might affect health, interactions between an individual, a group or community, and the physical, social, and political environments have an impact on one’s health. Such frameworks enhance the generalizability and interpretability of research findings in addition to increasing research efficiency [ 21 ].

Addressing the complex nature of eye health requires a comprehensive understanding of effective interventions, their implementation, and their impact on various populations [ 22 ]. Despite the existence of numerous interventions and strategies for eye health promotion which improve the uptake of eye care services, there is limited evidence on a comprehensive synthesis and evaluation of their effectiveness across diverse populations and settings [ 10 ]. Research that is currently available often focuses on specific interventions or particular populations, which could limit the generalizability of findings and hinder the establishment of broad approaches for the promotion of eye health [ 23 ]. This systematic review aims to address this gap by synthesizing evidence on a wide range of interventions for eye health promotion, including but not limited to preventive measures, educational programs, community outreach initiatives, and healthcare service delivery models [ 24 ]. Acknowledging the evidence will guarantee that interventions are customized to the contextual, socioeconomic, and cultural aspects affecting the health outcomes and behaviours related to eye health [ 25 ].

Study design

This systematic review protocol is part of a larger study, “Developing an eye health promotion intervention framework within a primary health care setting in Limpopo Province, South Africa: A Mixed-Method Study”. This systematic review protocol was designed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol Extension (PRISMA-P) The PRISMA-P checklist is included S1 Table [ 26 ]. The protocol is registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022354299) https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022354299 .

The methodology for the proposed systematic review will adhere to the guidelines for conducting systematic reviews in healthcare provided by the Centre for Reviews and Dissemination (CRD) [ 27 ]. In addition, a meta-analysis conforming to the standards of the Meta-analysis of Observational Studies in Epidemiology (MOOSE) will be carried out provided adequate data are available and studies are similar to interventions and outcomes [ 28 ]. This will be reported following the PRISMA 2020 statement: an updated procedure for reporting systematic reviews to ensure all necessary seven steps have been followed.

Step 1: Identifying the review question.

Participants were not involved in the design and development of the study protocol. However, iterative consultation with key informants was conducted to define the research questions. Thus, to determine the research question’s eligibility for a systematic review project, the review question was guided by the Centre for Reviews and Dissemination (CRD) guidance for conducting systematic reviews in healthcare framed in terms of the population, intervention(s), comparator(s) and outcomes of the studies to be included [ 27 ].

The systematic review will address the following research questions;

• What are the barriers and facilitators in the implementation of eye health promotion interventions?
• What is the nature and effectiveness of interventions for eye health promotion?

Step 2: Eligibility criteria for considering studies for the systematic review.

The eligibility criteria for considering studies for inclusion in this review are developed according to the relevant elements of the PICOd-T (Study Design—Time) framework in line with the research question [ 29 ]. The PICOd-T framework will be followed to ensure that the boundaries of the proposed systematic review research question are clearly defined [ 29 ]. Thus, eligible studies will be included after two reviewers have independently, reproducibly, and systematically evaluated them. Studies should present evidence on either of the factors, as illustrated in the S2 Table .

Participants will include studies among healthcare professionals residing in any part of the world. Interventions will consist of any interventions or a combination of interventions aimed at influencing the timeliness of symptomatic eye health diagnosis and screening asymptomatic individuals along any or all of the five key areas/ core focus of the Ottawa Charter framework for health promotion, whether as a single-focus intervention or a multi-focus intervention targeting multiple eye health services. The outcome will involve any clinical outcome, including (but not restricted to) improved access to eye health care, behavioural change, prevention of blindness, improved visual acuity and evidence-based policy and legislative change. The review will include primary studies from randomised controlled trials, quasi-experimental, observational and qualitative studies that are peer-reviewed. Research studies reporting on any other interventions that do not promote eye health will be excluded. The standard of care will represent the comparator. Outcomes of interest will include any or all of the outcomes or target goals of the Ottawa Charter framework for health promotion, such as improved access to early diagnostic services, reduced diagnostic time, and others—authors of studies published only as abstracts will be contacted and asked to provide further details. If no further detail is available, the source will be excluded. A third reviewer will resolve any disagreements between the two reviewers; furthermore, two reviewers will test the inclusion/exclusion criteria through piloting to establish agreement before commencing the study selection process.

Step 3: Search strategy for the identification of studies addressing the review question.

Systematic, comprehensive, and reproducible searches of reputable bibliographic databases, and indexing services (and platforms), followed by other supplementary information sources, will be conducted to capture primary studies addressing the main review question. Two reviewers will perform all the direct electronic and supplementary systematic searches using a pre-defined and piloted search strategy with the assistance of a professional librarian. Both electronic bibliographic database searching and additional search techniques will be covered by the search strategy to find published and unpublished (grey) literature that will be screened for inclusion in this study. The World Health Organization package will inform our search strategy of eye care interventions. A preliminary search for existing systemic reviews on this topic under review was conducted on 20 November 2023 in PubMed, EBSCOhost platform and Web of Science. The initial search strategy was developed in PubMed with 17,804 references identified. The search will be conducted in English and the authors acknowledge that literature in another language will be missed. The manuscript will recognize implicit constraints by referencing relevant literature, such as the study conducted by Amano et al,(2016) which suggests that relying solely on English-language sources may result in overlooking approximately 35% of relevant literature [ 30 ].

The first author, a librarian and a subject specialist, co-developed the comprehensive search strategy S3 Table . All authors will be given an equal opportunity to review the draft to ensure the correct use of indexing terminology and Medical Subject Headings (MeSH) descriptors before pilot testing on a subset of records from the Web of Science database. The details of the search strategy metrics–descriptors and truncation used, as well as the number of returned pilot records, are presented in S3 Table –this primary search strategy will then be adapted for other databases. A search summary table (SST) will be used to report on the search strategy methods and their effectiveness S5 Table .

Electronic search sources

Advanced systematic searches employing the piloted search strategy will be conducted from the following electronic databases to source articles published from the inception of the Vision 2020 campaign in 1999 to November 2023: WEB of Science, PubMed, and EBSCOHost Web (Academic Search Complete, CINAHL Complete, MEDLINE with Full Text, CINAHL with Full Text and Health Source: (Nursing/Academic Edition). Furthermore, randomized controlled trials that report evidence on health promotion interventions will be sourced from the South African National Clinical Trial Register and ISRCTN registry.

All three electronic databases (PubMed, EBSCOhost platform and Web of Science) will be searched during the search strategy according to the criteria. This process aims to obtain the maximum number of sources from the electronic databases and ensure that all relevant articles or reports are captured before the study selection and eligibility screening process begins.

Searching other resources–supplementary information search

In addition, supplementary search methods will include hand-searching of relevant journals, reference lists of identified peer-reviewed articles and grey literature, and as well as forward and backwards citation chasing. The reviewers will further browse through the link entitled "Related Articles" option, which searches for similar citations using an intricate algorithm that scans titles, abstracts, and MeSH terms to detect more studies.

Systematic reviews and other review papers are not eligible for inclusion; however, reference lists of relevant reviews, preprints, and conference abstracts will be screened for more relevant primary studies not captured by the search strategy. Furthermore, the appropriate trial publications reference lists will be checked for unidentified randomized clinical trials.

The systematic search management

The search summary table (SST) will be used to document the effectiveness of the search strategy, the systematic searches performed across databases, information used to inform the PRISMA-2020 flow diagram S2 Fig , and the search methods, as well as the additional information gathered by the librarian or information specialist in their search log. Using the SST format to present the information mentioned above will allow for calculating various search effectiveness metrics, and reporting these metrics shows the effectiveness of search strategies for each database and database searching as a whole. Furthermore, reporting these metrics separately increases the transparency of the search and study selection process.

The SST will be completed in two stages. In stage one, all the references that the search strategy retrieves from each electronic database, including all duplicates, will be exported to EndNote X9 (version 19.1.0.12691)–a reference management software, which will be used to create a virtual library (Thomson Reuters, Stamford, CT, USA). Every record in the virtual library will be given a code for the database name where the record was found. Stage two involves re-running the searches in the databases where most of the included references were found to determine whether references not found during the original search were in the database and, if so, whether the search strategy retrieved them.

Step 4: Study selection and eligibility screening.

The procedure for study selection and screening for eligibility will be carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) 2020 guidelines in S2 Table . A PRISMA-2020 style flowchart will be produced detailing the study selection and screening process and the reason for excluding each full-text paper reported as illustrated in S2 Fig .

The study selection and screening procedure will be done in three folds: Title screening, abstract screening and full-article screening; each stage will be guided by data screening tools developed in Google format (see Supplementary Information for examples of the data screening tools). The abstracts and titles of references retrieved by the electronic searches will be screened independently by two reviewers using the pre-specified inclusion/exclusion criteria S1 Table . Discussions will resolve discrepancies with a third reviewer (JTC) if necessary.

The full text of potentially relevant studies will be obtained following the abstract and title screening stages. Furthermore, guided by the same methods, the full text of articles deemed eligible will be assessed for inclusion by two reviewers. Using Stata 13.0SE (Stata Corp College Station, TX, USA), the Cohen’s Kappa coefficient (κ) statistic will be used to assess the disagreements between the two reviewers. When measuring inter-rater reliability, Cohen’s Kappa coefficient (κ) statistic is a reliable statistical technique [ 31 ]. In order to settle disagreements that have been identified between the two reviewers, a third reviewer will be asked for input.

Step 5: Data extraction/ or collection process.

The data extraction process will be informed by the template for intervention description and replication (TIDieR) checklist and guide for describing interventions S5 Fig . The overarching purpose of the TIDieR checklist is to prompt authors to describe interventions in sufficient detail to allow their replication. The checklist contains the minimum recommended items for describing an intervention. Thus, for this study and to ensure that the data collection process is reproducible, a standardised data extraction tool prepared in a Google Form format, based on the TIDieR checklist, will be used for extracting relevant data to characterize included studies (see Supplementary Information for examples of the data screening tools). Feedback was solicited from all authors regarding the draft list of data variables for extraction. The final data extraction tool will be calibrated and piloted for reliability and applicability on the first three eligible studies to maintain accuracy and ensure all necessary information is captured.

Quantitative data will be extracted by the first author/ or reviewer into a piloted, standardized data extraction form; the second reviewer will check this, and discrepancies will be resolved by discussion with the involvement of a third reviewer (JTC) if necessary. For qualitative studies, details of the study aim, the sample, and the type and nature of the intervention/programme, as well as data on the theoretical approach, the methods used to collect the data, the analytic processes and the quotes, themes and concepts pertinent to our research questions will be extracted into a piloted standardized data extraction form. Two reviewers working simultaneously and independently will conduct this process to exhibit strong inter-rater reliability. Any discrepancies will be resolved through discussion. A structured summary will be produced for each paper, and the extracted data will be tabulated, allowing comparison between studies S7 Table .

Requests for missing data

Missing data will be identified and recorded within the review. Where means and standard deviations are not available, we will collect effect estimates, confidence intervals, test statistics, P values and individual participant data where reported. Where papers provide insufficient details about the intervention, such as what is delivered and by whom, an effort would be made to contact the authors to obtain previously unpublished information and clarify any missing data.

Step 6: Assessment of study methodological quality and risk of bias.

The methodological quality and risk of bias of each included study will be assessed by two reviewers independently, using appropriate methodological quality assessment tools depending on the design of the included studies.

Tools to assess the methodological quality

As recommended, the mixed-method appraisal tool (MMAT) version 2018 will be used to determine the methodological quality of the included studies [ 32 ]. The MMAT appraisal tool consists of two core assessment domains addressing the external validity (risk of selection, data collection and non-response bias) and five further assessment domains addressing the internal validity (systematic error—the risk of measurement bias and bias related to data analysis) deemed relevant to appraise the methodological quality of various studies. To generate an overall methodological quality assessment, a percentage quality score will be calculated for each included study based on the evaluation of each domain and the overall risk of bias across domains. The scores will be interpreted as low quality if ≤ 50%, average quality if 51–75%, and high quality if 76–100%.

Tools to assess risk of bias (or study limitations)

The risk of bias in individual studies will be assessed using a suitable tool by one reviewer (VPN), checked by a second reviewer (MXR), and any disagreement will be resolved by discussion involving a third reviewer (HCM) if necessary. To determine the effectiveness and cost-effectiveness of interventions for eye health promotion, details on effect measures used to describe effect sizes in included studies and meta-analyses, such as risk ratio or odds ratio, mean difference or standardized mean difference, will be extracted. However, only measures most adjusted for one or more sets of potential confounders, such as socio-demographic and lifestyle factors, will be extracted to reduce confounding and measurement errors, ensure consistency across studies and reduce bias. The most appropriate measures for synthesis will be used, depending on the availability and appropriateness of available data, and document our decision-making processes.

Tools to assess the certainty of evidence (quality of evidence)

The quality of quantitative evidence will be ascertained using the current Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines for evaluating the certainty of a body of evidence [ 33 ]. The GRADE-CERQual will be used to establish the degree of confidence that may be placed in the qualitative evidence synthesis findings; and the results will be reported alongside the Summary of Findings table, together with a justification for judgement, in the ‘Included studies’ section. In the case of a CRT, a special variant of the RoB 2 tool focusing mainly on group participants from the clusters will be used [ 33 ].

Step 7: Collating, summarizing, and reporting the results.

The proposed systematic review aims to integrate health promotion interventions in practice by health professionals within the framework of the Ottawa Charter and also identify barriers and facilitators in the implementation of eye health promotion interventions using a Social-Ecological framework. Initially, upon the completion of the data extraction phase, a summary of findings table created from the collected data from the included studies will be generated, presenting a descriptive numerical description of the data. The descriptive summary of the findings table will include each of the pre-specified outcomes S2 Table , and details of the characteristics of the included studies, such as the total number of publications included, type of study design, year of publication, type of risk factors reported, characteristics of the study populations, and study setting.

Secondly, a world map will be modelled using Canva version 2.93.0, an interactive web-based graphic design application, in order to display the patterns of variation in the incidence, distribution, and trends of the studies that were selected for review. Thirdly, tables and figures will be used to present the results in an organized way to satisfy the main research question addressed by the proposed systematic review.

We will collate the data using an NVivo version 12 to present a narrative account of the literature through content thematic analysis of the included studies. Excerpts of text will be coded deductively by the reviewers to identify concepts and themes related to the research questions. The resulting themes will be analysed and the result will inspect the relationship between the research questions and the findings. In this step of the systemic review, we will provide a summary of the evidence applying the five key action areas of the Ottawa Charter to chat the outcomes. The Social-Ecological model for health promotion will be used as a framework to synthesize and categorize facilitators and barriers influencing the implementation of eye health promotion interventions. The meaning of the findings will be considered as they relate to the overall study purpose and the implications of these findings for future research, policy, and practice.

3. Discussion

Our systemic review builds on reviewing literature addressing health promotion interventions practised by eye health professionals within the context of primary healthcare. This systemic review aims to collect evidence on the health promotion interventions practised by eye health professionals within the framework of the Ottawa Charter and also identify barriers and facilitators in the implementation of eye health promotion interventions using a Social-Ecological framework. It is anticipated that findings from this review identify gaps and guide future research to bridge the gaps toward improved health outcomes for individuals using primary eye care services. The results of this review will guide eye care services implementers in designing health promotion interventions that will help improve individuals’ engagement with primary eye care services in South Africa.

Health promotion is one of the strategies recommended by the WHO World Report on Vision to address eye care needs [ 9 ]. Health promotion interventions such as awareness and education are important aspects of an eye health action plan that seeks to address causative factors of various burdens of eye diseases such as cataracts, glaucoma, and blinding uncorrected refractive errors [ 16 ]. The burden of eye diseases has serious consequences on the social determinants of health which can be mitigated by appropriate access to quality eye care [ 9 ]. In sub-Saharan Africa, health care is mostly provided through the public health service [ 34 ]. District Health Service (DHS) consists of primary, secondary, and tertiary levels, which in most instances focus on providing curative care. DHS is associated with barriers to accessing eye care, limited engagement with communities, a shortage of appropriately skilled health personnel, and inadequate support from health systems [ 34 ]. Global action plans for the prevention of avoidable blindness and visual impairment recommend an increase in public awareness and use of eye healthcare services [ 35 ].

Our findings expect to have relevant studies on health promotion interventions by health professionals at different levels of care. Therefore, the evidence of this systemic review will guide eye health professionals in planning intervention strategies to address public health concerns in eye health. The findings will guide further implementation research on health education interventions for eye health. We will present this review at scientific conferences on health promotion and distribute it online or in print. To the best of our knowledge, no systemic review studies on health promotion interventions by health professionals have been conducted previously.

4. Strengths and limitations of the study

The strength of this study is that it will apply a broad review of multidisciplinary databases covering ophthalmology, medicine general internal, paediatrics, surgery, health care science services, public environmental occupational health, clinical neurology, endocrinology metabolism, multidisciplinary science, medicine research experimental and other Web of Science Core Collection Citation Topic. This approach will provide a comprehensive assessment of published literature on courses designed on these subjects as illustrated in S6 Fig .

This is a significant systemic review to synthesize qualitative and quantitative evidence on the nature and effectiveness of interventions for eye health promotion practised by health professionals within different levels of care. This review will broaden to inform study research for the development of a framework to guide the implementation of eye health interventions in South Africa. Health promotion practitioners and relevant stakeholders will be engaged throughout the study. A systemic review approach was chosen for this phenomenon as other reviews may suffer from publication bias. The review is also limited to studies published in English which may bias the evidence.

Supporting information

S1 fig. pico framework for determining the eligibility of the research question..

https://doi.org/10.1371/journal.pone.0305904.s001

S2 Fig. PRISMA 2020 flow diagram outlining the study selection and eligibility.

https://doi.org/10.1371/journal.pone.0305904.s002

S3 Fig. Title & abstract screening form.

https://doi.org/10.1371/journal.pone.0305904.s003

S4 Fig. Full-text screening form.

https://doi.org/10.1371/journal.pone.0305904.s004

S5 Fig. Distribution of publications selected from Web of Science core collection by categories.

https://doi.org/10.1371/journal.pone.0305904.s005

S6 Fig. Distribution of publications selected from Web of Science core collection citation topic.

https://doi.org/10.1371/journal.pone.0305904.s006

S7 Fig. Distributions publications (Topic).

https://doi.org/10.1371/journal.pone.0305904.s007

S1 Table. PRISMA-P checklist.

https://doi.org/10.1371/journal.pone.0305904.s008

S2 Table. Eligibility criteria (PICOd-T).

https://doi.org/10.1371/journal.pone.0305904.s009

S3 Table. Search strategy.

https://doi.org/10.1371/journal.pone.0305904.s010

S4 Table. Meta-analysis data capturing sheet.

https://doi.org/10.1371/journal.pone.0305904.s011

S5 Table. Search summary.

https://doi.org/10.1371/journal.pone.0305904.s012

S6 Table. Categories of themes and subthemes of interest.

https://doi.org/10.1371/journal.pone.0305904.s013

S7 Table. Data extraction.

https://doi.org/10.1371/journal.pone.0305904.s014

Acknowledgments

The authors would like to extend their appreciation to Xolani Masuku and Portia Nelisiwe Vezi for technical support and the University of KwaZulu-Natal (UKZN) for the provision of resources for this review.

• View Article
• Google Scholar
• PubMed/NCBI
• 7. World Health Organization, "Ottawa Charter for Health Promotion First International Conference on Health Promotion, 1986," Geneva: WHO, 2010.
• 9. World Health Organization. "World report on vision." https://www.who.int/publications/i/item/9789241516570 (accessed 07 April, 2022).