Evidence based medicine can’t be . . . * Adam La Caze University of Sydney alacaze@mac.com Abstract Evidence based medicine (EBM) puts forward a hierarchy of evi- dence for informing therapeutic decisions. An unambiguous interpre- tation of how to apply EBM’s hierarchy has not been provided in the clinical literature. However, as much as an interpretation is provided proponents suggest a categorical interpretation. The categorical inter- pretation holds that all the results of randomised trials always trumps evidence from lower down the hierarchy when it comes to informing therapeutic decisions. Most of the critical replies to EBM react to this interpretation. While proponents of EBM can avoid some of the prob- lems raised by critics by suitably limited the claims made on behalf of the hierarchy, further problems arise. If EBM is to inform therapeutic decisions then a considerably more restricted, and context dependent interpretation of EBM’s hierarchy is needed. 1 Introduction Evidence based medicine (EBM) proposes that medical decisions be based on the best available evidence. Despite achieving a level of orthodoxy over the past 15 years, EBM continues to be intensely debated in sections of the medical literature (Miles et al., 2006). EBM has also recently gained the * The final and definitive version of this paper is published in Social Episte- mology, 22:4,3553–370. The paper is available online at informaworld at DOI: http://dx.doi.org/10.1080/02691720802559438. Please reference published paper. 1