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Systematic Reviews: The PICO Framework

An introductory guide to Systematic Reviews

The PICO Framework

The first key stage of a systematic review would be to formulate a focused, answerable research question. A well-defined and clear research question is an essential starting point for a systematic search. To create a logical search strategy, always start by identifying the key elements of the research question - i.e., establish what the main concepts of the topic are. With these concepts, you can then create the search blocks that form the basis for the search strategies used in the different databases.

Use the PICO framework to translate the research question into search concepts that can be applied in a structured search strategy. In general, you should not use all parts of the PICO question in the search. The key focus of the search would be generally on the P (Population / Patient / Problem) and the I (Intervention), and sometimes C (Comparison intervention) if the volume of search results is too great, or the concept is exceptionally clear and regularly reported.     

Karolinska Institutet University Library (2022). Systematic reviews [Systematic Search Techniques] :

PICO for Quantitative Studies

Patient, Population or Problem Intervention Comparison Intervention Outcome

The patient, population or problem which the question applies to.

Drugs, surgical and therapeutic procedures being evaluated. What is the alternative intervention? (e.g. placebo, different drug, surgery, gold standard) The clinical outcomes of interest.

An example of the use of PICO (Quantitative)

Formulate a clear and focused PICO question. An example of an initial unfocused question would be: Is caffeine effective in preventing daytime drowsiness (DTD)?

A focused clinical question would be: Among adults with a history of DTD, does a cup of caffeinated coffee in the morning improve alertness? A question is made focused by clearly specifying the PICO elements...

P: adults with a history of DTD
I: A cup of caffeinated coffee in the morning
C: No caffeinated coffee (implied)
O: Alertness

Dr Lorraine Tudor Car. 1.2 Focused Question & the Parallel Group RCT Design.

Further Reading

St Joseph's Health Centre Toronto. Study Design [Matching Question Types with Study Design].

Elsevier Author Services. FINR : a Research Framework.

PICO for Qualitative Studies

P I Co

What are the characteristics of the patient or population?

What is the condition or disease you are interested in?

The phenomena of Interest relates to a defined event, activity, experience or process Context is the setting or distinct characteristics. Note: Context, not comparator.

Murdoch University Library. [2022]. Using PICO or PICo - Systematic Reviews:

Other Frameworks (For Qualitative Studies)

An example of a qualitative research question: Do mindfulness programs improve the academic, behavioral, and socio-emotional functioning of primary and secondary students?

Let's apply this to the SPIDER framework.

S Sample Group Pre-school, primary and secondary students



Phenomenon of Interest Mindfulness programs
D Design (Specific Methodology) Quasi-experimental design (QED)
E Evaluation

Socio-emotional outcomes

Behavioral outcomes

Academic outcomes

R Research Type Mixed Methods

Another example of a qualitative research question: What is the effect of climate change on the seed quality of legume crops?

Let's apply this to the SPICE framework.

S Setting (where?) n/a (global - all countries)
P Perspective (for who or what?) Legumes
I Intervention (phenomenon of interest) Elevated CO2
C Comparison No elevation in CO2
E Evaluation (Outcome)

Seed mass


Seed vigour

Steven Chang (La Trobe University). Systematic Searching for Systematic Reviews.