The Pyramid Schema: The Origins and Impact of Evidence Pyramids

Abstract

Evidence pyramids are amongst the most recognisable visual artefacts of the Evidence-Based Medicine movement. Yet no study has established the origins of evidence pyramids, or analysed whether they offer any information beyond simple lists or tables. In this paper, I trace the origins of the first evidence pyramid, to a tutorial published online by SUNY Downstate at the latest in 1997. Demonstrating that there is no valuable additional information conveyed by a pyramidal structure in contrast to a simple table or list, I then argue that the pyramidal turn is a retrograde step in evidence appraisal, due to the restricted use of conditions and non-categorical interpretations which this design format incentivises.

Keywords: Evidence-Based Medicine, Evidence Pyramids, Hierarchy of Evidence