Systematic reviews and meta-analyses: a step-by-step guide

Step 3

a) Formulate the problem (see presentation on Systematic Literature Searching Sheila Fisken)

Clearly establish what your question is: consider using PICO:

  • Patient/Person: who does this relate to?
  • Intervention (or cause, prognosis): what is the intervention or cause?
  • Comparison (Is there something to compare the intervention to?)
  • Outcome (What outcome are you interested in?).

This may need several revisions, and some ‘scoping’ of the literature, to find something that is specific and answerable. A clear, specific and answerable question is essential to a successful review.

b) Has this been done before?


To avoid wasting your time and energy, establish whether this question has already been answered in the published literature, or is registered as an ongoing review (e.g. search in DARE, which contains abstracts of quality assessed systematic reviews and details of all Cochrane reviews and protocols, or NHS EED which contains abstracts of quality assessed economic evaluations:

c) Consider registering your review

This will ensure that others know yours is ongoing (and many journals will now look for registration to ensure high quality reviews which do not deviate from pre-defined criteria are published).

•         For interventions, or accuracy of a diagnostic tests:

           –        Cochrane:

•         For social interventions in education, crime and justice, social welfare:

           –        Campbell Collaboration:

•         For reviews in health or social care:

           –        Prospero:


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