5.1. What Should My Literature Review Cover?

At its most basic level, a literature review is a survey of factual or nonfiction books, articles, and other documents published on a particular subject. That said, when you are writing a literature review for an empirical study (either one you are proposing or one you have already completed), it is better to think of your literature review as an argument for your research problem and the research question that addresses it. Specifically, the literature review summarizes and synthesizes what is currently known about a topic while identifying one or more gaps in that knowledge. Answering your proposed study’s research question should help fill the gap that your literature review has uncovered.

Unlike the “research papers” you have written in other classes, your literature review will not just make an argument with sources. Unlike an annotated bibliography, it will not just summarize sources. Instead, it will relate those sources to your study’s research question. It will make an argument for the importance of your research problem and the need for your proposed or completed study.

All literature reviews will at some point:

1. Introduce the topic and define its key terms.
2. Establish the importance of the topic (i.e., answering the “so what?” question—why exactly we should care about this phenomenon, issue, or problem).
3. Put forward one or more research questions to be examined, and provide an overview of the relevant scientific literature on any concepts covered by that question, along with any related concepts.
4. Identify aspects of a phenomenon where there is not enough research and where scientists lack a full understanding (i.e., the topic is “understudied”).
5. Point out areas of scholarly agreement where studies have consistently come to the same conclusions, as well as areas of controversy where no such consensus exists.
6. Arrive at a synthesis that organizes and categorizes what is known about a topic—not just summarizing any related studies, but prioritizing the studies most relevant to the research question and highlighting the key takeaways and omissions in each related body of research.
7. Discuss the implications and limitations of previous studies and the directions that future research might take to address any gaps in that literature. When conducting a literature review for a new research project, this will entail justifying the current study—flagging one or more research problems and stating how the proposed or completed study will resolve them.

There are many different types of literature reviews, including those that focus solely on methodology, those that are more conceptual, and those that are more exploratory. When they are part of a write-up of original empirical research, literature reviews usually appear as a section near the beginning of the proposal or paper. They are meant to justify the proposed or completed study, and the literature review section will be followed by a discussion of the new study’s methods (and for completed studies, its findings). However, literature reviews can also be stand-alone documents. To provide other scientists with an overview of a noteworthy area of research, scholars will write long-form literature reviews called review articles, which may cover fairly broad topics of scientific interest (such as the review articles that the Annual Review of Sociology routinely publishes, which discuss the state-of-the-art sociological research on a given subject). To inform policymakers about the relevant scientific knowledge on a pressing policy area, social scientists sometimes write policy briefs that break down the findings of previous research, often in layperson’s terms.

Regardless of their goal and audience, strong literature reviews have similar characteristics. They should be original works based on an extensive critical examination and synthesis of the relevant existing research on a topic. They should be reasonably complete summaries of the current state of scholarly understanding—that is, not restricted to a few journals, a few years, or just one methodology. And they should be arranged by key themes or findings, concluding with a discussion of areas where research is needed.

The scientific impact that your proposed research study will have depends on what others have found before you. In your literature review, try to place the study you wish to do in the context of previous research and ask, “Is this contributing something new?” and “Am I addressing a gap in knowledge or a controversy in the literature?” If you review the existing literature well, you will learn whether your initial research questions have already been addressed in the literature, and whether there are newer or more interesting research questions available. In this way, your literature review provides assurances that you are not repeating a study done many times before and that you are not making an obvious error that others have already encountered.

As we noted in the last chapter, you will undoubtedly revise and refocus your working research questions in light of what you find during your review. Note that drafting the literature review, much like reworking your research question, is an iterative process—one that stops, starts, and loops back on itself multiple times before completion. You will often find yourself reading more as you work through your literature review, and stopping your reading to make sense of what you’ve just read by writing it up. Resist the urge to try to read “everything” and then draft your review in one sitting; instead, give yourself permission to shift between the two modes of reading and writing, which build upon each other.

By reading what others have argued and found in their work, you become familiar with how people talk about and understand your topic. You encounter theories that have previously been used to address similar research questions. And you piece together possible answers to your specific questions, which will become your study’s hypotheses in your later research proposal.

As you begin your literature review, here are some common errors to avoid:

1. Accepting another researcher’s finding as valid without evaluating their methodology and data. Based on your training as a researcher, you can read other scholars’ papers and determine for yourself whether the data and methods they used were adequate. You can also assess the validity of a particular study’s findings by comparing them to what others have found; in general, your literature review should prioritize results obtained from superior data and methods.
2. Ignoring contrary findings and alternative interpretations. In a literature review, you will want to describe the degree of scientific consensus regarding the phenomenon of interest, and you should make sure to point out any disagreement. Likewise, you should discuss all the possible explanations for a phenomenon—not just the one you favor—and assess the evidence in an evenhanded manner.
3. Dedicating insufficient time to literature searching. To be a good scholar, you need to be a good reader of scholarship. Intensively reading the available literature will gradually give you a sense of where the existing research falls short, and what interesting questions still need to be asked.
4. Reporting isolated results rather than synthesizing them. As opposed to just noting findings, one study after another, try to categorize them and group together similar studies in your discussion. Then identify any consistent findings in the literature, along with any exceptions and disagreements. Try to present those findings in a hierarchical order, highlighting the key points and subpoints—perhaps broken up into separate sections of the literature review, and then in separate paragraphs in each section. For studies that are more pertinent to your research question, you will want to describe both their findings and their methods at greater length.
5. Relying too heavily on secondary sources. As we discuss later, you can use review articles and other summaries or commentary on previous empirical studies (secondary sources) to help guide you in your search of the literature, but you should not lean too heavily on them. You need to read the actual empirical studies, which will sharpen your understanding of where your own study can contribute.
6. Overusing quotations from sources. You only need to use quotations in a literature review when you want to pass along a particularly consequential or eloquently written statement from another author. Otherwise, just paraphrase. Summarizing other people’s work in your own words makes your writing livelier and has the added benefit of helping you internalize that information.
7. Using findings that are not clearly related to your own study or using findings that are too general. As we discuss further below, your discussion of the literature should be focused enough that you are not talking in minute detail about studies that are not closely related to your own.
8. Not justifying arguments using specific facts or theories from the literature. In a literature review (and in any part of an academic paper, for that matter), you need to back up any claims that are not universally accepted. If other scholars have already provided theories or evidence of these claims, you should summarize those theories and empirical findings and cite the authors. If a theory is not adequately supported with empirical evidence, you should make a note of that. And you should be transparent about any lack of evidence more generally, qualifying your statements in the literature review to convey that a particular claim “may” be true, is “suggested” by the limited data available, and so on.