Developing Your Question Using PICO
PICO is an acronym for:
- Patient
- Intervention
- Comparison
- Outcome
PICO is used to create a researchable question based on a clinical situation you have encountered. Based on your PICO question, you will identify keywords and/or subject terms to use in database searches.
You can use PICO to develop your clinical question.
P - Patient or population/disease:
Which population are you studying? (Consider age, gender, ethnicity, group with a certain disorder, etc.)
I - Intervention, prognostic factor, or exposure
What do you want to do for the patient? (Consider therapy, exposure to a disease, risk behavior, prognostic factor, preventative measure, or diagnostic test)
C - Comparison or control
Are you comparing two interventions or variables? (Consider absence of disease, absence of risk factor, or use of placebo)
O - Outcome
What is the expected result or what do you hope to accomplish, improve or affect? (Consider disease incidence, accuracy of a diagnosis, rate of occurrence of adverse outcome, survival or mortality rates)What is the expected result or what do you hope to accomplish, improve or affect? (Consider disease incidence, accuracy of a diagnosis, rate of occurrence of adverse outcome, survival or mortality rates)
Study Design Tree
Figure from Tree of different types of studies, CEBM, https://www.cebm.net/2014/04/study-designs/
Spotting the Study Design
The type of study can generally be worked at by looking at three issues (as per the Tree of design in Figure 1):
Q1. What was the aim of the study?
- To simply describe a population (PO questions) ► descriptive
- To quantify the relationship between factors (PICO questions) ► analytic
Q2. If analytic, was the intervention randomly allocated?
- Yes? ► RCT
- No? ► Observational study
For observational study the main types will then depend on the timing of the measurement of outcome, so our third question is:
Q3. When were the outcomes determined?
- Some time after the exposure or intervention? ► cohort study (‘prospective study’)
- At the same time as the exposure or intervention? ► cross sectional study or survey
- Before the exposure was determined? ► case-control study (‘retrospective study’ based on recall of the exposure)"