At the heart of your systematic review is your research question. This is the 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 answer a specific, focussed question in a systematic way). It can be challenging to formulate the ‘right’ question for your topic, but it’s important that you spend time making sure the question:
Relates to what you really need to know about your topic
Is specific and focused
Is relevant to your field
Has not (recently) been answered by anyone else
Your question will guide your search strategy and data analysis, so it’s very important to figure it out early in the process.
Three types of questions were proposed by Eldredge (2002). These question types can also be related to more clinical questions:
||(Why does D change with E in population F? Or What causes D to change in population F?)|
||(Will X affect Y? Or How will X affect Y? Or How will X progress over time?)|
||(Will J perform better than K at achieving outcome L?)|
It’s important to work out what type of question you are asking.
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.
There are lots of frameworks you can use to organise these concepts. Here we’ll focus on the popular ‘PICO’ format (Richardson et al. 1995). See below for other frameworks.
P, I, C and O each represent different concepts that will be part of the question:
For questions where C = comparison:
For questions where C = control:
There are variants of PICO that prompt you for other concepts, such as time (PICOT) or research type (PICOR)
As well as PICO there are many other frameworks for conceptualising your question:
Wildridge, V., & Bell, L. (2002). How CLIP became ECLIPSE: a mnemonic to assist in searching for health policy/management information.
Health Information and Libraries Journal, 19(2), 113-115. doi: 10.1046/j.1471-1842.2002.00378.x
Cooke, A., Smith, D., & Booth, A. (2012). Beyond PICO: The SPIDER tool for qualitative evidence synthesis.
Qualitative Health Research, 22(10), 1435-1443. doi: 10.1177/1049732312452938
Booth, A. (2006). Clear and present questions: formulating questions for evidence based practice,
Library Hi Tech, 24(3), 355-368. doi: 10.1108/07378830610692127