Levels of Evidence

What are the levels of evidence?
http://www.cebma.org/frequently-asked-questions/what-are-the-levels-of-evidence
CEBMa center for Evidence-Based Management

Levels of Evidence for Primary Research Questions
North American Sports Medicine Institute & Advances in Clinical Education
September 2011
http://rehabeducation.com/go/levels-of-evidence
Therapeutic studies. Prognostic studies. Diagnostic studies. Economic and Decision Analyses.

Levels of Evidence
http://www.sbimc.org/2001/fall/Ramaekers/sld013.htm

A classification for the levels of evidence used for therapeutic studies in EBM.
October 2012
http://lifeinthefastlane.com/cicm-saq-2012-1-q17