What is Evidence-Based Medicine?: Defining and Critiquing the Theory and Practice of Evidence-Based Medicine
Bulcock, Jennifer Anne
Engelhardt, H. Tristram
Doctor of Philosophy
Over the past 23 years evidence-based medicine (EBM) has been incorporated into the healthcare systems of the United States, the Netherlands, Australia, England and many other countries in the developed world. Despite its widespread acceptance, foundational questions persist regarding what EBM is and whether its foundational assumptions are justified. It is the contention of this project that EBM cannot be coherently understood as a singular, unified theory of medicine. Rather, it is most appropriately conceived of as a cluster concept or brand name under which several theories are constructed and are characterized to varying degrees by EBM’s four primary principles: 1) randomized controlled trials (RCTs) are the gold standard research methodology, 2) clinicians should distrust authorities, 3) clinical experience and clinical expertise are not high quality sources of evidence and 4) standardization of medical practice is an ideal. Particular focus is given to EBM’s theory of clinical practice and its theory for assessing research evidence of clinical effectiveness (the “rules of evidence” or “evidence-hierarchy). EBM’s theory of clinical practice and its historical genesis are expounded and analyzed. It is argued that EBM’s initial articulation of a theory of clinical practice had to be abandoned because it was impossible to realize in practice. Further, given its most recent articulation, it is maintained that EBM no longer constitutes a unique theory of clinical practice because it permits too much variance. EBM’s theory for assessing research evidence of clinical effectiveness is also carefully analyzed. It is argued that EBM’s hierarchy of evidence (i.e., a categorical ranking of research methodologies) is unjustifiably founded on the epistemological assumptions that 1) RCTs have a superior ability to identify causal relationships between treatments and their effects and 2) RCTs produce less biased results. Additionally, it is argued that the RCT’s limited external validity causes further epistemic and practical problems for the evidence hierarchy. Accordingly, it is argued that the current categorical interpretation of the evidence hierarchy is epistemically unjustifiable and therefore should be abandoned.
evidence-based medicine; philosophy of medicine; randomized controlled trials