Evidence-Based Practice

Levels of Evidence/Sources of Evidence



These include clinical pathways or textbook summaries that integrate evidence-based information about specific clinical problems and provide regular updating.


FirstConsult @ Clinical Key

National Guideline Clearinghouse

Evidence Based Textbooks



Systematic reviews are critically appraised syntheses of the best evidence on an individual question. Several organizations create systematic reviews; the most well known is the Cochrane Collaboration. Well-done systematic reviews gather the best studies, usually randomized controlled trials, using a detailed and comprehensive search strategy. They identify those studies of the best quality that ask similar questions and appraise them in a systematic way.

The Cochrane Database of Systematic Reviews

The Database of Abstracts of Reviews of Effect (DARE)

Systematic Reviews are also searchable in MEDLINE:

Ovid MEDLINE: Systematic Reviews

PubMed: Clinical Queries


Single studies

Original research studies still have great value in the EBP model. The key is being able to identify the best evidence from the millions of articles published. In databases like PubMed and CINAHL searchers can employ Clinical Query search tools or limit to individual publication types.

The Cochrane Database of Systematic Reviews


Ovid Medline



Adapted from Houser J, Oman KS. (2011). Evidence-based practice: an implementation guide for healthcare organizations. Sudbury, Mass: Jones and Bartlett Learning, p.179-180.

※ see Levels of Evidence Pyramids