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Systematic Review: Develop question

Copy of published guide 'systematic review' (Paula Todd version) for Editing taken in July 2021

Develop a question

At the heart of your systematic review is the research question that you are trying to answer. (A systematic review is not just a list of things different articles say, but a much more in-depth attempt to synthesise the evidence to answer a specific, focused question in a systematic way). Your question will guide your search strategy and data analysis, so it’s very important to figure it out early in the process.

It can be challenging to formulate the ‘right’ question for your topic, but it’s important that you spend time making sure the question:

  • Is answerable

  • Is specific and focused

  • Has not (recently) been answered by anyone else


Three types of questions were proposed by Eldredge (2002, p. 10). These question types can also be related to more clinical questions:

  • Exploration/Etiology
(Why does D change with E in population F? Or What causes D to change in population F?)
  • Prediction/Prognosis
(Will X affect Y? Or How will X affect Y? Or How will X progress over time?)
  • Intervention/Therapy/Diagnosis
(Will J perform better than K at achieving outcome L?)

A good question will combine several concepts (e.g. the D, E and F above). Identifying the relevant concepts is crucial to successful development and execution of your systematic search.

Check if your question has been answered

Before starting, it’s really important that you ensure that your research question has not already been effectively answered in a recent review, and that no reviews on the topic are planned or already in progress.

Reviews in progress (or prospective systematic reviews) may be referred to as protocols. A protocol clearly documents what the reviewers intend to do in their systematic review.

Some sources listing current protocols:

Some sources of published systematic reviews:

It is also possible to search for systematic reviews in many key databases. For example, all Cochrane reviews are indexed in the Medline database.