T (for time interval) and S (for setting ) may also be added to the PICO question.
PICO is a method for answering a question using evidence. PICO usually has the following elements:
P = Patient or Population
I = Intervention or Indicator
C = Comparison or Control
O = Outcome
Useful PICO guides:
Centre for Evidence Based Medicine
Kansas University Medical Center - A.R. Dykes Library
UAB Libraries - U of Alabama at Birmingham
University of North Carolina Health Sciences Library