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Psychology Research Methods and Statistics

This Research Guide supports PSY 303.

Literature Review Overview - North Carolina State University

Writing a Literature Review

What is a literature review?

Scholarship -- the process of doing, documenting, and sharing research -- is a kind of ongoing conversation. One of the most important things researchers do when they participate in that conversation is help each other to understand the current state of the discussion and talk about future developments. In order to do this, researchers write literature reviews, in which they pull together (synthesize) previous work on a subject and present it in the context of their own claims, so that they can show other researchers how their work contributes new information to the conversation.

Remember: A good literature review is NOT just a report on what other researchers have already done -- it's a tool for identifying trends, themes, and issues in previously published research for the purpose of assembling evidence in support of future research.

How do I write a literature review?

In order to write a literature review, you need to take the following basic steps:

1. Assemble relevant, current articles, studies, and other resources on or related to your topic

2. Identify what they have in common, where they differ, and what the impact of their results might be.

3. Assemble and organize the information identified in step (2) and present your results to your reader, either in the form of a literature review section in a paper/study or in the form of a systematic review of the literature.

Not sure how to do (2) and (3)? You're in luck! We've got some models and guidance for you in this Guide! The Synthesising Sources tab will take you to some basic writing help for pulling together and presenting your review and some info and templates for using synthesis and research tables for figuring out what to talk about and organizing your work. The Evaluating Sources tab includes a Levels of Evidence table and PICOT question resources to help you to assess the content of the articles you find. The Models & Advice tab provides a set of links out to sites with more information, examples, and helpful tips for writing literature reviews.

Synthesis, step by step

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

  1. Identify and clearly describe your research question (you may find the Formulating PICOT Questions table at the Evaluating Sources tab helpful).
  2. Collect sources relevant to your research question.
  3. 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 Evaluating Sources tab), and briefly explain their major findings. Use a Research Table to document this step.
  4. 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.
  5. 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.

Research and Synthesis Tables

Research Tables and Synthesis Tables are useful tools for organizing and analyzing your research as you assemble your literature review. They represent two different parts of the review process: assembling relevant information and synthesizing it. Use a Research table to compile the main info you need about the items you find in your research -- it's a great thing to have on hand as you take notes on what you read! Then, once you've assembled your research, use the Synthesis table to start charting the similarities/differences and major themes among your collected items.

We've included an Excel file with templates for you to use below.

PICOT Questions and Levels of Evidence

*Note: sometimes, you will encounter PICO instead of PICOT; some research or clinical questions omit the Timeframe element

PICOT format table


The figure below is an adaptation of the levels of evidence as presented by Melnyk and Fineout-Overholt (2015, p.11). According to the authors, these levels should be viewed hierarchically in terms of  objective reliability and generalizability; with Level I representing the most generalizable and objective evidence, and Level VII representing the least generalizable evidence with a greater risk of bias (p.92).





Levels of Evidence and PICOT charts adapted from:

‚ÄčMelnyk, B. Mazurek, & Fineout-Overholt, E. (2015). Evidence-based practice in nursing and healthcare: a guide to best practice. Third edition. Philadelphia: Wolters Kluwer Health


How do I determine the correct level of evidence for a study?

All of the clues you need to determine a study's level of evidence are provided in that study's methods section, which is where the authors describe the study's design. You may find this link to the Centre for Evidence-Based Medicine's basic study design guide helpful for figuring it all out:

Tutoring and Writing Assistance at USI

Your first stop for help with your writing here at USI should be the Tutoring programs in the Academic Skills department. You can schedule an appointment with a tutor or send your work to the Online Writing Lab for feedback from a writing consultant.

Your Liaison Librarian can also help you get started on the literature review process, as well as offering some assistance for correctly formatting your work and including correct citations.