PICO is a framework for asking focused clinical questions.
PICO stands for:
Patient and Problem
Intervention or exposure
Comparison or Control
Hierarchy of Evidence Summary
Level I: a. Evidence of a systematic review or meta analysis of all relevant randomized controlled trials (RCT), or evidence-based clinical practice guidelines based on the above.
b. Evidence of a systematic review of RCTs
c. Evidence of a systematic review of nonrandomized trials
Level II: a. Evidence from at least 1 RCT.
b. Single nonrandomized trial
Level III: Evidence from a systematic review of correlational/observational studies
Level IV: Evidence from a single correlational/observational study
Level V: Evidence from systematic reviews of descriptive, qualitative or physiologic studies.
Level VI: Evidence from a single descriptive, qualitative, or physiologic study.
Level VII: Evidence of authority opinion or reports of expert committees.
Pyramid modified from: Navigating the Maze, University of Virginia, Health Sciences Library, by University of Washington. Health Sciences Library and Information Center
Cochrane Database of Systematic Reviews:
Other Systematic Reviews and Meta-Analyses:
RCTs, Case Cohorts, Control Studies
Clinical Research Critiques
Other Reviews of the Literature
Case Reports, Case Series, Other Articles, Practice Guidelines
Clinical Reference Texts:
Resources for Critiquing the Quality of your Sources:
Basic Information and Tutorials about EBP: