Another way to gather sources and present the information you have gathered utilizing primarily summaries is a literature review. This type of project is a survey of everything that has been written about a particular topic, theory, or research question. The word “literature” means “sources of information.” The literature will inform you about the research that has already been conducted on your chosen subject. This is important because we do not want to repeat research that has already been done unless there is a good reason for doing so (i.e. there has been a new development in this area or testing a theory with a new population, or even just to see if the research can be reproduced). Literature reviews usually serve as a background for a larger work (e.g. as part of a research proposal), or it may stand on its own. Much more than a list of sources, an effective literature review analyzes and synthesizes information about key themes or issues.
Purpose of a literature review
The literature review involves an extensive study of research publications, books, and other documents related to the defined problem. The study is important because it advises you, as a researcher, whether the problem you identified has already been solved by other researchers. It also advises you as to the status of the problem, techniques that have been used by other researchers to investigate the problem, and other related details.
A literature review goes beyond the search for information and includes the identification and articulation of relationships between existing literature in your field of research. The literature review enables the researcher to discover what has been already been written about a topic and to understand the relationship between the various contributions. This will enable the researcher to determine the contributions of each source (books, article, etc.) to the topic. Literature reviews also enable the researcher to identify and (if possible) resolve contradictions and determine research gaps and/or unanswered questions.
Even though the nature of the literature review may vary with different types of studies, the basic purposes remain constant.
- Provide a context for your research;
- Justify the research you are proposing;
- Show where your proposed research fits into the existing body of knowledge;
- Enable the researcher to learn from previous theory on the subject;
- Illustrate how the subject has been studied previously;
- Highlight flaws in previous research;
- Outline gaps in previous research;
- Show how your proposed research can add to the understanding and knowledge of the field;
- Help refine, refocus, or even move the topic in a new direction
What is involved in writing a literature review?
- Research – to discover what has been written about the topic;
- Critical Appraisal – to evaluate the literature, determine the relationship between the sources, and ascertain what has been done already and what still needs to be done;
- Writing – to explain what you have found
Generally speaking, it is helpful to think of the literature review as a funnel. One starts with a broad examination of the research related to the issue, working down to look at more specific aspects of the issue, which leads to the gap or the specific issue that your research will address.
How to undertake a literature review
The first step in undertaking a literature review is to conduct a library search of academic research that has been done on your topic. This can be done electronically, or if you are within close vicinity to a library, you can go in and use their computers to find electronic and print holdings. You can also use Google Scholar for your search. In some cases, research conducted outside academia can serve as an important research source for your literature review. Indeed, such research can have important practical implications, as opposed to academic research which usually (although not always) tends toward theoretical applications.
However, it is important to understand who funded the research you review, in addition to the perspective and the purpose of the research. Review Chapter 2 “Warming Up: The Ins and Outs of Sources” to recap how to vet sources and where to find them.
As part of this first step, there are a few more things to be thinking about as you review the literature
- Who are the various researchers who have studied this topic? Who are the most prolific researchers/writers on this topic? Has a specific researcher or teams of researchers been identified as pioneers or leaders in this field of study?
- How have the various researchers defined key terms that are relevant to your topic? Have the definitions of any of the key terms evolved over time?
- What are the different theories that have been examined and applied to this topic? How, if at all, have the various theories applied to this topic over time evolved?
- What methodologies have been used to study this topic? Have the methodologies evolved over time?
In addition to thinking about these questions, you should be taking notes during this process. If you are finding your sources online and viewing them as PDFs via a database, you can download the file and annotate as you read using software like Adobe Reader and Kami. Annotating, according to Webster, is “a note added by way of comment or explanation.” Simply put, it means actively reading and taking notes during the process of your research. For a lot of people, this boils down to highlighting/underlining passages, charts, graphs, and data that they interpret as important to the overall article’s purpose. This also includes drafting comments in the margins that explain the thought process you had when you decided that the information you marked was important. Annotating may feel time-consuming and, to some, like “busy work,” but if you trust the process, when you go to put together the project using those sources, it will be much easier as you will have your own thoughts to review in order to track back why you kept a source and why you wanted to use it as evidence in your research project.
Your notes for a source should include marking (either by highlighting or drafting a note) information similar to the following.
- If the article is empirical, write down the results of the research study in one or two sentences of your own words. e.g. “people who are between ages 18 – 35 are more likely to own a smart phone than those above or below.” It is also a good idea to make note of the methods, the research design, the number of participants and details on the sample used in the study. Sometimes, you may even want to write down the names of the statistical procedures used to analyze the data or even some of the statistics, depending on your assignment.
- If the article is a review of previous research, look for the main points. It may be helpful to read or skim the whole article, look away, and ask yourself what you felt was the main idea.
- Write down any limitations or gaps you notice, anything that seems to contradict something you read elsewhere, or just anything that you think is important or interesting
When reading through your sources, remember that you are looking for the “big picture,” not a collection of separate articles all tangentially about the same topic (an annotated bibliography). You are also not trying to prove a point (an essay). You are looking for common themes and patterns in the research as a whole. You are also looking to see how the various pieces of research are linked, if at all. As part of this process, you also want to identify research gaps or areas that require further research related to your topic. In this regard, you cannot be expected to be an expert on your topic. A suggestion for finding gaps is to read the conclusion section of the academic journal articles and conference proceedings your search has uncovered. Researchers often identify gaps in the research in their conclusion. They may even suggest areas for future research. However, remember, if a researcher suggested a gap 10 years ago, it is likely that the gap has now been addressed. To find a gap, look at the most recent research your literature review has uncovered (within 2-3 years of the current date). At this point in your search of the literature, you may realize that your research question needs to change or adapt. This is a fairly common occurrence, as when you first develop a research question, you cannot be sure what the status of the research area is until you undertake your review of the literature related to this topic. Finally, it is worth mentioning that it is very likely you will not include all of the resources you have read in your literature review. If you are asked to include 20 resources in your literature review, for example, expect to read approximately 30.
How to write a literature review
There are three parts to the literature review: the introduction, the body, and the conclusion.
- The introduction must identify the topic by briefly discussing the significance of the topic including a statement that outlines the conclusion to be drawn from the literature review.
- If your literature review is part of a larger work, explain the importance of the review to your research question.
- Defend the importance of the topic by giving a broad overview of the scope of the work you are reviewing. For example, if you are interested in post-traumatic stress disorder (PTSD) in paramedics, you might provide some stats to prove how much work time is lost by those suffering from PTSD.
- Clarify whether you are looking at the entire history of the field or just a particular period of time.
- Discuss and assess the research according to specific organizational principles (see examples below), rather than addressing each source separately. Paragraphs should discuss more than one source. Avoid addressing your sources alphabetically as this does not assist in developing the themes or key issues central to your review.
- Compare, contrast, and connect the various pieces of research. Much of the research you are reading should be connected. You may notice various themes within the research (i.e. effects of PTSD on sick time, effects of PTSD on families of paramedics, effects of PTSD on overall paramedic wellness, etc.). If you have undertaken a thorough review of the literature, you should start to see the bigger picture of how the research on this topic has evolved over time, who the main researchers are on this topic, and how the methods and theories related to this topic have changed (if at all).
- Summarize the works you are reviewing. Just as in any written assignment, use logical organization and clear transitions.
Based on your research, suggest where the research in the field will or should go next. If you are proposing your own research study, show how you will contribute to the field and fill in any gaps. The conclusion would also be a good place to defend the importance of the topic, now that you have demonstrated the current state of thinking in the field. You may also want to consider noting any gaps in your own research. Were their groups, questions, data, etc. that you did not look at in your research? If so, why?
Organization and source types in literature reviews
Table 3.3.1 provides some suggested organizational techniques, as well as instances when you might use these various techniques. The table also provides a writing sample to demonstrate the writing technique.
|Organization technique||Instances When to Use||Examples|
||When explaining key themes or issues relevant to the topic
This is the most common way to organize literature reviews.
A literature review of 31 relevant articles published between January 2005 and March 2015 identified 10 variables relevant to user adoption of mobile technology: Perceived usefulness, perceived ease of use, income/ wealth, employment, mobility requirement, education, social resources, etc.“User adoption variables” is the theme
||When discussing interdisciplinary approaches to a topic or when discussing a number of studies with a different approach.||In e-business adoption literature, various models have been used as a framework for analyzing the factors that need to be satisfied in order to guarantee business success. This review evaluates the different models used in this area with the intent of determining if standardized methodologies exist.|
|3. Chronologically||When historical changes are central to explaining the topic.||A literature review is presented on the evolution of post-traumatic stress disorder and its impact on firefighters from the late 1970s through to the present time. As part of this evolution, you might discuss how the definition of PTSD has evolved over time, how the methods used for studying this topic have evolved over time, how treatment options have evolved over time, etc.|
Acceptable sources for literature reviews
There are sources that are considered more acceptable for literature reviews. Below they are listed in order from what is considered most acceptable to less acceptable sources for literature review assignments.
- Peer reviewed journal articles;
- Edited academic books;
- Articles in professional journals;
- Website material from professional associations (use sparingly and carefully);
Peer reviewed journal articles (papers)
A peer reviewed journal article is a paper that has been submitted to a scholarly journal, accepted, and published. Peer review journal papers go through a rigorous, blind review process of peer review. What this means is that two to three experts in the area of research featured in the paper have reviewed and accepted the paper for publication. The names of the author(s) who are seeking to publish the research have been removed (blind review), so as to minimize any bias towards the authors of the research. Albeit, sometimes a savvy reviewer can discern who has done the research based upon previous publications, etc. This blind review process can be long (often 12 to 18 months) and may involve many edits on the behalf of the researchers, as they work to address the edits and concerns of the peers who reviewed their paper. Often, reviewers will reject the paper for a variety of reasons, such as unclear or questionable methods, lack of contribution to the field, etc. Because peer reviewed journal articles have gone through a rigorous process of review, they are considered to be the premier source for research. Peer reviewed journal articles should serve as the foundation for your literature review.
Edited academic books
The papers within the text also go through a process of review; however, the review is often not a blind review because the authors have been invited to contribute to the book. Consequently, edited academic books are fine to use for your literature review, but you also want to ensure that your literature review contains mostly peer reviewed journal papers.
Articles in professional journals
Articles from professional journals should be used with caution, as far as it relates to a source for your literature review. This is because articles in trade journals are not usually peer reviewed, even though they may appear as such. A good way to find out is to read the “About us” section of the professional journal. They should state there if the papers are peer reviewed. You can also google the name of the journal and add peer reviewed to the search and you should be able to find out that way.
Website material from professional associations
Material from other websites can also serve as a source for statistics that you may need for your literature review. As you want to justify the value of the research you are interested in, you might make use of a professional association´s website to learn how many members they have, for example. As a hypothetical example, you might want to demonstrate, as part of the introduction to your literature review, why more research on the topic of PTSD in police officers is important. You could use peer reviewed journal articles to determine the prevalence of PTSD in police officers in Canada in the last ten years and then use the Ontario Police Officers´ Association website to determine the approximate number of police officers employed in the Province of Ontario over the last ten years. This might help you create an approximation of how many police officers could be suffering with PTSD in Ontario. That number could potentially help to justify a research grand down the road. But again, this type of website-based material should be used with caution and sparingly.
The Five ‘C’s of Writing a Literature Review
To help you frame and write your literature review, think about these five ‘c’s.
- Cite the material you have referred to and used to help you define the research problem that you will study.
- Compare the various arguments, theories, methods, and findings expressed in the literature. For example, describe where the various researchers agree and where they disagree. Describe the similarities and dissimilarities in approaches to studying related research problems.
- Contrast the various arguments, themes, methods, approaches, and controversies apparent and/or described in the literature. For example, describe what major areas are contested, controversial and/or still in debate.
- Critique the literature. Describe which arguments you find more persuasive and explain why. Explain which approaches, findings, and methods seem most reliable, valid, appropriate, and/or most popular and why. Pay attention to the verbs you use to describe what previous researchers have stated (e.g. asserts, demonstrates, argues, clarifies, etc.).
- Connect the various research studies you reviewed. Describe how your work utilizes, draws upon, departs from, synthesizes, adds to or extends previous research studies.
Difference between a literature review and an essay
So now that you know what a literature review is and how to write it, it is important to understand how a literature review is different from an essay. First of all, it is necessary to point out that many students struggle with understanding the difference between a literature review and an essay. This is particularly so because the exact same resources used to create a literature review can be used to create an essay; however, what is different about the two is where the emphasis in the writing is placed.
As discussed previously, a literature review focuses on everything that has been written about a particular topic, theory, or research. It is focused on the research and the researchers who have undertaken research on your topic. In contrast, an essay focuses on proving a point. It does not need to provide an extensive coverage of all of the material on the topic. In fact, the writer chooses only those sources that prove the point. Most professors will expect to see you discuss a few different perspectives from the materials that run contrary to the point you are trying to make. For example, suppose you want to write an essay about the negative effects of shiftwork on nurses. You would gather material to show that shiftwork negatively affects nurses, and the various ways it affects nurses. Now, in this case, you might find the odd research paper that states shiftwork has no effect – although, I doubt it, because it has been extensively documented to have a negative effect. However, the point is that with an essay you are focused on providing information on your topic and proving your point which means that your argument should not be in a literature review as that type of paper is not about what you believe or want to argue should be considered; it is about the current conversation you are planning to enter.
Difference between a literature review and an annotated bibliography
Another type of academic writing that can also confuse students who are attempting to write a literature review is one that you have already learned about in this chapter–the annotated bibliography.
However, the main difference between an annotated bibliography and a literature review falls on the level of synthesis that happens among the sources. In an annotated bibliography (like we discussed earlier in this chapter), you are creating stand-alone summaries about each source in your paper. These sources should be related in the sense that they are all about the same general research topic; however, in this type of paper, you do not have to look for connections beyond making sure they are discussing the same topic. In a literature review, you have to link the sources to one another (which means your summaries are typically much shorter in a literature review than they are in an annotated bibliography). You move from writing one summary about each source in a single paragraph to connecting several condensed summaries about 2 or more sources in one paragraph. A literature review focuses more on creating a big picture between the sources by grouping like sources together and using transition phrases/words to develop a link between said sources or synthesizing.
Synthesis as Conversation Among the Authors of Your Source Materials
To synthesize is to combine ideas and create a completely new idea. That new idea becomes the conclusion you have drawn from your reading. This is the true beauty of reading: it causes us to weigh ideas, to compare, judge, think, and explore—and then to arrive at a moment that we hadn’t known before. We begin with summary, work through analysis, evaluate using critique, and then move on to synthesis.
How do you synthesize?
Synthesis is a common skill we practice all the time when we converse with others on topics we have different levels of knowledge and feelings about. When you argue with your friends or classmates about a controversial topic like abortion or affirmative action or gun control, your overall understanding of the topic grows as you incorporate their ideas, experiences, and points of view into a broader appreciation of the complexities involved. In professional and academic writing, synthesizing requires you to seek out this kind of multi-leveled understanding through reading, research, and discussion. Though, in academic writing, this is another kind of discussion: you set the goal for the discussion, organize the discussion among the authors of your found researched materials, orchestrate the progress of the discussion, build logical guidance for your audience, and finally you draw your conclusion on the topic.
Below are some steps you can use to help you synthesize research:
- Determine the goal(s) for your discussion such as reviewing a topic or supporting an argument
- Organize the discussion among the authors of your found researched materials
- Lead the discussion among the authors of your sources
- Summarize the most vivid of the authors’ examples and explanations
- Finally, draw your unique conclusion on the topic: in fact, the answer to your research question
What synthesis is NOT
Synthesizing does not mean summarizing everyone’s opinion: “Julia is pro-life, and Devon is pro-choice, and Jasmine says she thinks women should be able to have abortions if their life is in danger or they’ve been the victims of rape or incest.”
Synthesizing does not mean critiquing opinions: “Rick tried to defend affirmative action, but everyone knows it’s really reverse racism.”
Synthesizing does not simply compare texts (unless assigned as such by your instructor). You are neither evaluating nor comparing the effectiveness of the authors’ presentations.
What synthesis IS
Instead, synthesis demonstrates YOUR full, objective, empathetic understanding of a topic from multiple perspectives. When you synthesize, you “cook” the ideas and opinions of others by thinking, talking, and writing about them, and what comes out is a dish full of many blended flavors but uniquely your recipe:
Notice that this synthesis does not crouch behind limited and thoughtless positions: “You can’t change the Second Amendment!” “Ban all guns!” This synthesis instead tries to depict the hard reality: guns are an integral part of American culture, and so is gun violence, and limiting the latter can not be done without impacting the former. This synthesis reserves judgment and aims for understanding. In order to gain an unbiased and fair understanding of a topic, you must read research from all sides of the conversation (even if you think you disagree with that side before you begin researching).
- 3.3 (excepts where otherwise noted) was borrowed with minor edits and additions from An Introduction to Research Methods in Sociology by Valerie A. Sheppard which is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License ↵
- relatively speaking. It is a daunting task to read EVERYTHING that has ever been written on a topic (especially in a semester); however, literature reviews are composed of multiple sources covering a specific topic--much like an annotated bibliography. ↵
- Adjei, J. K. (n.d.). Research methods. Retrieved from African Virtual University website: https://oer.avu.org/handle/123456789/490 ↵
- Ibid. ↵
- Editage Insights. (2021, March 3). Q: Which is considered the highest academic publication among a book, an edited book, and a book chapter? https://www.editage.com/insights/which-is-considered-the-highest-academic-publication-among-a-book-an-edited-book-and-a-book-chapter ↵
- Adjei, J. K. (n.d.). Research methods. Retrieved from African Virtual University website: https://oer.avu.org/handle/123456789/490 ↵
- Derived from Callahan, J. L. (2014). Writing literature reviews: A reprise and update. Human Resource Development Review, 13(3), 271 –275. https://doi.org/10.1177/1534484314536705 ↵
- Thomas, J. (2012, September 26). Literature review vs. essay [Blog post]. Retrieved from https://blogs.qut.edu.au/library/2012/09/26/literature-review-vs-essay/ ↵
- Borrowed with minor edits and additions from "5.2 Synthesizing in Your Writing" by Yvonne Bruce, Melanie Gagich, and Svetlana Zhuravlova which is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License ↵