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Subject LibGuides

Systematic Reviews: Formulating a Research Question

Formulating a Research Question

It is important to define the area that you want to research in order to develop an effective search strategy.

The key to this is to be very specific in terms of what you want to find.

Different disciplines have models for constructing research questions and we have listed these below.

The review question

The question will determine the nature and scope of the review; will identify the key concepts to be used in your search strategy; and will guide which papers you are searching for.

When devising the question it is advisable to ask an open question rather than making a statement but not one that would lead to a simple 'yes' or 'no' answer. As your question should be comprehensive and specific, it should only include one question and ideally have three for four elements as suggested by the frameworks given on this page.

The type of research questions you might see include:

  Treatment or therapy





  Patient's experiences and attitudes


SPIDER is an alternative to PICO that has a special focus on qualitative research.

Sample - The group of people being looked at, because qualitative research is not easy to generalize, sample is preferred over patient.

Phenomenon of Interest - Looks at the reasons for behaviour and decisions, rather than an intervention.

Design - The form of research used, such as interview or survey.

Evaluation - The outcome measures.

Research type - Qualitative, quantitative and/or mixed methods.

More information on the SPIDER method can be found at the link below.



Population or  Patient

the person affected by what you are researching - what are their defining characteristics and what is the condition they are experiencing?

  I Intervention

how are they being treated

 C Comparison

is there another treatment method that you would like to compare the intervention to?

 O Outcome

what is the result of the intervention? These can be primary and secondary outcomes

PICO is used in the Health and Medicine disciplines to define research questions by pointing to 4 components that can be used as above.


PICOT and PICOS are very similar to PICO but adds an extra element.

In PICOT, the T stands for Time, and indicates how long from the intervention outcomes will be looked for.

In PICOS, the S stands for Study Design, such as cohorts or randomized controlled trials.

It is possible to include all elements when structuring your research question.

Defining your studies

It's useful to determine which kind of studies you wish to include in your review before starting the search and this will help with your decisions around inclusion and exclusion criteria.

The table below gives an outline of the types of studies you might come across:

Quantitative Qualitative
Case reports Phenomenological
Cohort studies Ethnographic
Randomised controlled trials Grounded theory research design
Systematic reviews