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Systematic Reviews: Formulate your question and protocol


This video illustrates how to use the PICO framework to formulate an effective research question, and it also shows how to search a database using the search terms identified. The database used in this video is CINAHL but the process is very similar in databases from other companies as well.

Recommended Reading


A longer on the important pre-planning and protocol development stages of systematic reviews, including tips for success and pitfalls to avoid. 

* You can start watching this video from around the 9 minute mark.*

Formulate Your Question

Having a focused and specific research question is especially important when undertaking a systematic review. If your search question is too broad you will retrieve too many search results and you will be unable to work with them all. If your question is too narrow, you may miss relevant papers. Taking the time to break down your question into separate, focused concepts will also help you search the databases effectively.

Deciding on your inclusion and exclusion criteria early on in the research process can also help you when it comes to focusing your research question and your search strategy.

A literature searching planning template can help to break your search question down into concepts and to record alternative search terms. Frameworks such as PICO and PEO can also help guide your search. A planning template is available to download below, and there is also information on PICO and other frameworks (Adapted from:

Looking at published systematic reviews can give you ideas of how to construct a focused research question and an effective search strategy.

Example of an unfocused research question: How can deep vein thrombosis be prevented?

Example of a focused research question: What are the effects of wearing compression stockings versus not wearing them for preventing DVT in people travelling on flights lasting at least four hours.

In this Cochrane systematic review by Clarke et al. (2021), publications on randomised trials of compression stockings versus no stockings in passengers on flights lasting at least four hours were gathered. The appendix of the published review contains the comprehensive search strategy used. This research question has focused on a particular method (wearing compression stockings) in a particular setting (flights of at least 4 hrs) and included only specific studies (randomised trails). An additional way of focusing a question could be to look at a particular section of the population.

Clarke  M. J., Broderick  C., Hopewell  S., Juszczak  E., and Eisinga  A., 20121. Compression stockings for preventing deep vein thrombosis in airline passengers. Cochrane Database of Systematic Reviews 2021, Issue 4. Art. No.: CD004002 [Accessed 30th April 2021]. Available from: 10.1002/14651858.CD004002.pub4


There are many different frameworks that you can use to structure your research question with clear parameters. The most commonly used framework is PICO:

  • Population
    This could be the general population, or a specific group defined by: age, socioeconomic status, location and so on.
  • Intervention
    This is the therapy/test/strategy to be investigated and can include medication, exercise, environmental factors, and counselling for example. It may help to think of this as 'the thing that will make a difference'.
  • Comparator
    This is a measure that you will use to compare results against. This can be patients who received no treatment or a placebo, or people who received alternative treatment/exposure, for instance.
  • Outcome
    What outcome is significant to your population or issue? This may be different from the outcome measures used in the studies.

Adapted from:

Other Frameworks: alternatives to PICO

As well as PICO, there are other frameworks available, for instance:

  • PICOT: Population, Intervention, Comparison, Outcome, Time.
  • PEO: Population and/or Problem, Exposures, Outcome
  • SPICE: Setting, Population or Perspective, Intervention, Comparison, Evaluation
  • ECLIPS: Expectations, Client Group, Location, Impact, Professionals Involved, Service
  • SPIDER: Sample, Phenomenon of interest, Design, Evaluation, Research type

This page from City, University of London, contains useful information on several frameworks, including the ones listed above.

Develop Your Protocol

Atfer you have created your research question, the next step is to develop a protocol which outlines the study methodology. You need to include the following:

  • Background
  • Research question and aims
  • Criteria for inclusion and exclusion
  • Methods:
    • search strategy
    • selecting studies for inclusion
    • quality assessment
    • data extraction & analysis
    • synthesis of results
    • dissemination
  • Time frame

To find out how much has been published on a particular topic, you can perform scoping searches in relevant databases. This can help you decide on the time limits of your study.

Adapted from:

Register Your Protocol

It is good practice to register your protocol and often this is a requirement for future publication of the review.

You can register your protocol here:

Adapted from: