PICO is a method of reducing a clinical situation to a more easily understood and answerable question.
P: Population / Patient
Who or What? Patient, Population, Problem.
How would you describe a group of patients similar to your group?
What are the most important characteristics of the patient? Primary problem; disease; co-existing conditions.
Consider sex, age and/or race of a patient as this may be relevant to the diagnosis or treatment of a disease.
I: Intervention / Indicator
How: Intervention, prognostic factor or exposure - Drug, procedure, diagnostic test, exposure.
Which main intervention, prognostic factor, exposure are you considering?
What do you want to do for the patient? Prescribe a drug? Order a test? Order surgery?
What factor might influence the prognosis of the patient? Age; co-existing problems.
What exposure has the patient experienced? Asbestos; cigarette smoke.
C: Comparator / Control
What is the main alternative? Comparison or intervention?
What is the main alternative to compare with the intervention?
Are you trying to decide between? Two drugs; a drug and no medication or placebo; two diagnostic tests.
Your clinical question may not always need a specific comparison.
What are you trying to accomplish, measure, improve, effect, achieve?
What can you hope to accomplish measure, improve or affect?
What are you trying to do for the patient? Relieve or eliminate the symptoms; reduce the number of adverse events; improve function or test scores.
Always evaluate the outcomes in regard to the current issue and to future situations.
Clinical problem: A patient asks if drinking carrot juice will reduce the likelihood of developing prostate cancer.
Answerable clinical question:
P: In males
I: Does drinking carrot juice
C: Compared to not drinking carrot juice
O: Reduce the incidence of prostate cancer