Evidence-Based Practice: PICO

PICO helps you to structure an answerable clinical question. The PICO approach also helps you build a search strategy by clearly identifying all parts of the clinical question:

Patient or problem
How would you describe a group of patients? What is the problem? What illness? What age?

Intervention, exposure, or prognostic factor
What main intervention are you considering? What do you want to do with this patient?

Comparison
Are you considering an alternative intervention, or no intervention?

Outcome
What are you trying to accomplish, measure, improve or affect?

It may be helpful to identify the following in more detail:

Type of intervention

Type of study

What do you want to do for this patient or group of patients?

Therapy
Select the best treatment for a diagnosis.

Diagnosis
Select the best diagnostic test for a diagnosis.

Prevention
Select the best preventive measure for a disease.

Harm or etiology
Identify causes or risk factors for a disease.

Prognosis
Identify a patient's likely clinical course over time.

Remember: PICO is a model and not a strict protocol. The PICO model tends to work better with therapy and diagnostic questions.

Study types are differentiated by strength of evidence. The type of intervention you're investigating will determine what kind of study is appropriate. Depending on your clinical question, the highest levels of evidence (systematic review and meta-analysis) may not be available:

Therapy
Double-Blind Randomized Controlled Trial (RCT) / Systematic Review / Meta-Analysis of RCT

Diagnosis
Controlled Trial / Systematic Review / Meta-Analysis of Controlled Trial

Prevention
Randomized Controlled Trial / Cohort Study

Harm or etiology
Cohort Study

Prognosis
Cohort Study / Case-Control Study / Case Series

From: Straus, Sharon E. Evidence-based medicine: How to practice and teach EBM.