Evidence-Based Medicine: Levels of Evidence

Chart produced by Bob Phillips, Chris Ball, Dave Sackett, Doug Badenoch, Sharon Straus, Brian Haynes, Martin Dawes since November 1998. Updated by Jeremy Howick March 2009 and made available through the Oxford Centre for Evidence-Based Medicine.

The CEBM “levels of evidence” were first produced in 1998 for Evidence-Based On Call to make the process of finding appropriate evidence feasible and its results explicit. They have revised the “levels” in light of new concepts and data and present them on this page.