Skip to Main Content

Literature Reviews

An introduction to the Literature Review process and resources to help you get started.


Questions vs Thesis statements

Questions and thesis statements both have the same purpose, which is to state what you are writing about and restrict your paper to a manageable topic.

  • A question is phrased as a problem to solve
  • A thesis statement is phrased as a tentative answer, but both sides of the question must still be considered in your research

Badke, WB 2014, Research strategies : finding your way through the information fog, iUniverse, Bloomington IN.


Question - Does eating chocolate improve cognitive function?

Thesis statement - Eating chocolate may improve cognitive function.

You may find it helps to think in terms of answering a question at the beginning of your research to avoid unintentionally biasing yourself toward one answer.

Preliminary research

Good research questions don't usually appear out of thin air.  You need to do some preliminary reading to understand the range of questions and answers relating to a topic before you can identify possible areas to focus on. 

You also need to consider the scope of your project, and make sure it is realistic given your timeframe and word count.

  • Is there enough research to review?
    If there is not enough written on your topic to review, you will need to widen your scope, or change your question.

  • Is there too much?
    If there is too much literature on your topic to review, you will have to focus more tightly on one aspect.

These decisions cannot be made before you start.  Only reading about the issues that are being discussed in the existing academic literature will give you enough background knowledge to choose an achievable focus for your review.

Review articles

One way to get an overview of the body of research on your topic is to look for published review articles.

What's the difference between a primary research article and a review article?
  • A primary research article is a description of a single study, investigation or experiment.
  • A review article is a summary and analysis of several other studies, investigations, and experiments.


Review articles summarise the current state of understanding on a topic.

They can help you find:

  • the main people working in an area of research
  • recent advances and discoveries
  • important primary research papers in the field
  • significant gaps in the research
  • current debates
  • suggestions about where research might go next

IMPORTANT: please resist the temptation to use a published review article as a direct template for your own review, because this makes it very easy to unintentionally plagiarise!


Generating ideas

Creating a mind map of topics from your preliminary reading can be a great way to generate ideas for possible research questions.  Mind mapping will allow you to:

  • See an overview of your topic
  • Identify connections between ideas and details
  • Group emerging themes together (colour coding works well for this)

mind map diagram showing central subject with branches to colour-coded sub-topics and further branches to 'must read' articles, controversies and debates, unanswered questions, and possible questions


If you prefer to create a digital mind map, there are loads of software options to choose form (try Coggle, XmindFreeplaneMindMeister, Ayoa, or MindNode), but I strongly urge you to consider using the traditional pen and paper method. 


Why go old-school?

Drawing your mind map by hand gives you complete freedom to concentrate on your ideas (and the relationships between them) without being distracted by trying to make software do what you want it to.

Your hand drawn mind map may not look pretty, but remember that this is a thinking tool.  It isn't supposed to be a work of art.

Refining your question

When you have done some preliminary reading and brainstorming, you will probably find that you have several ideas that could be turned into focused research questions.  One way to do this is the tried-and-true 5W+H method:


Question frameworks

There are also several frameworks that have been developed to help researchers structure effective questions and clarify main concepts.  They are often used in Evidence Based Practice methodology for the health sciences, but some can also be useful in other disciplines.

Even when your question does not fit perfectly into any one framework, using part of one to clarify your thinking can help tremendously.

Here are some of the most common frameworks:


Useful for: clinical research

Population / Problem / Patient Who is my question focused on?
What individual or group are we interested in studying?
Intervention / Issue What is the proposed new intervention?
What is the action (intervention, treatment) we are considering taking?

What is the current or alternative state?
To what other action (intervention, treatment) are we comparing the considered action?

(Note: this can include doing nothing)

Outcome What is the outcome being measured?
What do we anticipate as an outcome?

Richardson, WS, Wilson, MC, Nishikawa, J, & Hayward, RS 1995, 'The well-built clinical question: A key to evidence-based decisions', ACP journal club, vol. 123, no. 3, pp. A12-A12.



PIO Population; Intervention; Outcome
PICO+ Patient; Intervention; Comparison; Outcome;  context, patient values, and preferences
PICOC      Patient; Intervention; Comparison; Outcome; Context
PICOS      Patient; Intervention; Comparison; Outcome; Study type / Setting
PICOT      Patient; Intervention; Comparison; Outcome; Time / Timeframe / Timing


Further resources for using PICO

Developing Your Search Question using PICO/PIO/PEO (Teeside University)

Seven steps to the perfect PICO search (EBSCO - CINAHL Complete)

Clinical examples using PICO (CIAP - Clinical Information Access Portal)


Useful for: qualitative research

Population / Problem / Patient Who is my question focused on?
What individual or group are we interested in studying?

What pre-existing conditions does the patient/population have?
What has the patient/population been exposed to?

Outcome What is the outcome being measured?
What do we anticipate as an outcome?

Khan, KS, Kunz, R, Kleijnen, J, & Antes, G 2003, Systematic reviews to support evidence-based medicine: How to review and apply findings of healthcare research, London: Royal Society of Medicine Press.


Useful for: qualitative / mixed methods research focused on samples


Who are the group being studied?
Phenomenon of
What behaviours or experiences are being studied? 
What are the reasons for them - how and why?
Design How was the study devised and conducted?
How was the data collected?
Evaluation What is being measured in they study, and how?
(This is likely to be subjective rather than empirical)
Research type What type of research is it - qualitative, quantitative, or mixed methods?

Cooke, A, Smith, D, & Booth, A 2012, 'Beyond PICO: The SPIDER tool for qualitative evidence synthesis', Qualitative Health Research, vol. 22 no. 10, pp. 1435-1443.


Useful for: qualitative research examining a policy or service

Expectation What are you want to improve or change?
What is the information going to be used for?
Client group Who is the service for?
Location Where is the service run from?
What change in service are you investigating?
Professionals Who is involved in providing or improving the service?
Service What kind of service is this?

Wildridge, V, & Bell, L 2002, 'How CLIP became ECLIPSE: A mnemonic to assist in searching for health policy/management information', Health Information & Libraries Journal, vol. 19, no. 2, pp. 113–115.


More frameworks

A review of 38 question frameworks

Supplementary material from: Booth, A., Noyes, J., Flemming, K., Moore, G., Tunçalp, Ö., & Shakibazadeh, E. (2019). Formulating questions to explore complex interventions within qualitative evidence synthesis. BMJ global health, 4(Suppl 1), e001107.