Literature Review

Literature Review, What is it, how to do it

A systematic literature review is one of the types of literature review that aims to summarize all existing information about a phenomenon in an impartial and complete manner.

In contrast to the non-systematic process, the systematic review is done in a formal and meticulous manner. This means that we must follow the plan defined in the review protocol, which, among other things, establishes a well-defined sequence of steps.

Due to this meticulousness, one of the advantages of the systematic literature review is to allow other researchers to make future updates of the review if they follow the same set of steps established in the protocol.

This article from summarizes the stages of a literature review in three phases: Planning the Review, Conducting the Review, and Reporting the Review. We will detail them below.

Planning for the Literature Review

The planning phase must be carried out with great care, as any errors that happen will have an impact on the other phases and their review may be totally compromised. The main way out of this phase is the review protocol.

To carry out the planning you must follow the following steps:

  1. Identify the need for a literature review. For that you have to reflect and try to answer the following questions:
    • Is the research area mature enough, with enough studies published?
    • Is there already a recent review on the same topic?
  2. Define the research questions you intend to answer with the review.
    • A critical part of the review, these questions are used to build the strings (keywords) to search for articles in the bibliographic bases.
    • They determine what information will be extracted from the articles to be analyzed, which we call primary studies.
    • Once defined in the planning phase, these issues cannot be changed in the following phases.
    • We recommend that an expert on the subject review the issues still in the construction phase of the protocol.
    • Literature reviews previously done in the same area, or in similar areas, may help to define these issues.
  3. Create the review protocol
    • In this protocol, the entire step-by-step to do the review is defined. The steps must be well defined and strictly followed to reduce the possibility of errors in the execution of the review.
    • All review authors must participate in the elaboration of the protocol.
    • It is important to simulate the execution of the protocol, which will help to find possible errors in each of the steps. During the simulation, research questions can still be changed.
  4. Validate the protocol
    • The fundamental step should be done with the help of the advisor or specialist in the area.
    • This step is very important since this protocol will determine how all research will be conducted.

IMPORTANT: You should only proceed to the next phase when you are sure that your protocol is ready. Repeat the planning steps as many times as necessary to be sure. Remember that any mistake in planning can compromise your entire research.

Conducting the Literature Review

The conduct of the review must strictly follow the protocol that was prepared. Below are the steps for conducting the review.

Search primary studies

  • There are three strategies and search for primary studies, they are:
    • Manual Search: when we visit the websites and/or annals of conferences and journals in search of articles on the researched topic.
    • Automatic Search: when we visit digital libraries to search for articles according to a certain keyword or set of them, which we call search strings. Examples of digital libraries: Google Scholar, Sage, ResearchGate, Science Direct, PubMed, etc.
    • Snow-Balling: when we analyze the list of article references in search of new studies.

Search strategies can be used individually or in combination. To ensure the completeness of your review, we advise you to combine the three strategies and use more than one digital library.

IMPORTANT: the search engine of each digital library works in a specific way. That way, you will have to elaborate your search strings according to each of the libraries.

Select primary studies:

In this step, you must select which studies will be considered in your review. That is, which ones will be analyzed.

Depending on the volume of studies captured in the previous step, we look at the title and abstract of these studies in order to eliminate irrelevant studies. It is common in some areas of research that the abstract (or summary) has little or low-quality information. In such cases, it is necessary to read the introduction and conclusion.

After this first filter, the full text of each article should be considered. For this, we apply the inclusion and exclusion criteria defined in the protocol to obtain the final list of primary studies that will be considered in the review.

Assess the quality of primary studies

It is important to assess the quality of primary studies to support the inclusion/exclusion process and assign a weight to specific studies so that they are considered in the data synthesis phase.

There is no universal definition of what a quality study is, but the literature suggests that these studies have little or no bias, and internal and external validities are maximized.

Quality assessment is widely used in health reviews.

Extract information from primary studies

We must identify and capture the information from each primary study. For this, the approach to be used is to answer each of the research questions with the information contained in these studies.

To reduce the bias of its review, a data extraction form must be defined and evaluated even in the protocol review phase.

An interesting approach for when we have a large number of primary studies is to have a researcher for data extraction and another to verify the data that have already been extracted.

Synthesize the information

Once the data has been extracted, it must be synthesized in a way that answers the research questions.

There are several techniques for performing this synthesis, such as narrative synthesis, meta-ethnography (meta-ethnography), grounded theory, thematic analysis/synthesis, etc.

Writing the systematic literature review

Once the questions are answered, the literature review should now be documented. That is, you will write a document about your review, which could be an article, a chapter of your research paper, etc. In this context, the question arises: how will I know what to write and what sections and subsections should I consider?

The following are the main sections and subsections of a  Literature Review:

  1. Introduction
  2. Related works
  3. Planning the review
    • Identification of the topic to be researched
    • Specifying research questions
    • Protocol construction and development
    • Protocol evaluation
  4. Conducting the review
    • Research identification
    • Selection of primary studies
    • Evaluation of studies.
    • Data extraction and monitoring.
    • Data synthesis
  5. Reporting the review
    • Explaining how the results will be shown
    • Sorting the data
    • Writing the results and their interpretation
    • Evaluating the results
  6. Threats to study validity
  7. Conclusion
  8. References
  9. Appendices


Finally, we recommend that you read the references and examples of systematic reviews we have selected below to learn more about this type of bibliographic review, as this article is not intended to be a complete guide.

If you have any questions or need help in writing your literature review papers, you can contact our customer service or send us a dissertation help request.

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