Skip to Main Content


Describes the PICO interface and how to use it effectively.

PICO Guide, Printable PDF

Medline's PICO Interface

Definition of PICO

PICO, an acronym for "patient, intervention, comparison, outcome," is a technique for formulating a question and inputting it into medical databases, such as Medline or CINAHL. It helps you think more clearly and input a better query. Some databases have a PICO interface, such as Medline. Others, like CINAHL, do not.


Explanation of the PICO Structure
Definition Description
P=Patient or Problem       Consider a description of the patient (age, gender, ethnicity) and/or the condition or disease.
I=Intervention What intervention or treatment is in question? This could be a drug, a test, a procedure, or an exposure.
C=Comparative intention    What is the alternative action you are considering? This may be left empty if there is not an alternative under consideration.
O=Outcome This is what you hope to accomplish, improve, or alter.


Screenshot of Medline's PICO interface

Subject Guide

Profile Photo
Lisa Bartle