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Systematic Reviews

Forming a Question

A systematic review starts with a well defined research question.

Points to keep in mind are - does it address the topic of interest, is it relevant to your field of research, is it focused and answerable, and will it add new research on the topic.

A number of frameworks can be used to break the review question into concepts.Some of these are listed in the Tools for Forming a Question box.

Inclusion and exclusion criteria

The review question will guide the search strategy and the conclusions, that can be drawn from the review, as these will depend on which studies or other forms of evidence are included and excluded from the literature review. At this point of forming the question, inclusion and exclusion criteria can be developed. In some instances a scoping search may be done before the inclusion and exterior criteria are determined.

Application of Question Types:


Clinical Questions


Qualitative Questions


Qualitative/Mixed Method 


Evaluating Projects or Interventions


Evaluating Services


Questions from Practice by Professionals Concerning Client’s Welfare


Tools for Forming a Question & Articles on Using the Tools

  • PICO (Population, Intervention, Comparison, Outcome)
    This is a commonly used tool for formulating focused clinical questions. It clarifies the question, determines search concepts, and identifies the type of study that is most appropriate to answer the question type.PICO model illustrated in a table

  • PICOT (Population, Intervention, Comparison, Outcome + T= Type of question/Type of study/Time ) or PICOS (PICO + S= Study type)

  • PICo (Population, Intervention, Co= Context)

PICO Worksheets:


 COPES (Client Oriented, Practical, Evidence Search)

COPES questions are from practice. They have three characteristics:

  • they are Client Oriented 
  • they concern problems that come from everyday Practice
  • they can guide an Evidence Search

​Summary: Client type and problem, what you might do, alternate course of action, what you want to accomplish. Can be applied in General Practice, Social Work etc.


PECODR (Patient, Exposure, Comparison, Outcome, Duration, Results)
Useful for clinical questions with case control studies and cohort studies. Duration (length of the follow up period), results (Number Needed to Treat or similar).


PIPOH (Population, Interventions, Professionals/Patients, Outcome, Health Care Setting)

Useful with guidelines.


Fervers, B., Latreille, J., Burgers, J., Paquet, L., Haugh, M., Poirier, M., . . . Philip, T. (2004). PIPOH: A new tool for use in clinical practice guidelines adaptation. Annals of Oncology, 15(S3), 151.