Flattening the Truth Pyramid: Reconsidering the Evidence Hierarchy

Abstract

For decades, the evidence hierarchy - which places randomized controlled trials (RCTs) and systematic reviews at its apex – has contributed positively to decision-to-treat considerations. Nonetheless, RCTs have often failed to reveal efficacy and safety concerns relating to the studied treatments. Moreover, many of the questions posed in clinical practice are best answered by means other than RCTs. This discussion examines the flaws in RCT statistical methodology that contribute to their limitations. It also presents novel methodologies, that combine RCT data with observational data, and thereby enable clinicians to make personalized treatment decisions for individual patients – something RCTs alone cannot do. Finally, this discussion explores what constitutes the best evidence to answer the many questions clinicians confront on a daily basis. The upshot is a flattened evidence hierarchy wherein RCTs, observational studies and novel methodologies are placed in their proper context, so that their relevance to clinical medicine is neither exaggerated nor ignored.