Hierarchy of Evidence Summary
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
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:
Journal Articles and Original Studies:
Clinical Research Critiques:
Case Reports, Case Series, Other Articles, Practice Guidelines:
Clinical pathways, textbook summaries, practice guidelines:
Basic Information and Tutorials about EBP:
Writing your topic a PIO, PICO, PICOT question: