Hierarchies of evidence are an important and influential tool for appraising evidence in medicine. In recent years, hierarchies have been formally adopted by organizations including the Cochrane Collaboration [1], NICE [2,3], the WHO [4], the US Preventive Services Task Force [5], and the Australian NHMRC [6,7]. The development of such hierarchies has been regarded as a central part of Evidence-Based Medicine, a movement within healthcare which prioritises the use of epidemiological evidence such as that provided by Randomised Controlled Trials. Philosophical (...) work on the methodology of medicine has so far mostly focused on claims about the superiority of RCTs, and hence has largely neglected the questions of what hierarchies are, what assumptions they require, and how they affect clinical practice. This thesis shows that there is great variation in the hierarchies defended and in the interpretations they are, and can be, given. The interpretative assumptions made in using hierarchies are crucial to the content and defensibility of the underlying philosophical commitments concerning evidence and medical practice. Once this variation is been identified, it becomes clear that the little philosophical work that has been done so far affects only some hierarchies, under some interpretations. Modest interpretations offered by La Caze [11], conditional hierarchies like GRADE [12-14], and heuristic approaches such as that defended by Howick et al. [15,16] all survive previous philosophical criticism. This thesis extends previous criticisms by arguing that modest interpretations are so weak as to be unhelpful for clinical practice; that GRADE and similar conditional models omit clinically relevant information, such as information about variation in treatments’ effects and the causes of different responses to therapy; and that heuristic approaches lack the necessary empirical support. The conclusion is that hierarchies in general embed untenable philosophical assumptions: principally that information about average treatment effects backed by high-quality evidence can justify strong recommendations, and that the impact of evidence from individual studies can and should be appraised in isolation. Hierarchies are a poor basis for the application of evidence in clinical practice. The Evidence-Based Medicine movement should move beyond them and explore alternative tools for appraising the overall evidence for therapeutic claims. (shrink)

Evidence-based medicine (EBM) puts forward a hierarchy of evidence for informing therapeutic decisions. An unambiguous interpretation 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 interpretation holds that all the results of randomised trials always trump 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 problems 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. (shrink)

While evidence-based medicine (EBM) is often accused on relying on a paradigm of 'absolute truth', it is in fact highly consistent with Karl Popper's criterion of demarcation through falsification. Even more relevant, the first three steps of the EBM process are closely patterned on Popper's evolutionary approach of objective knowledge: (1) recognition of a problem; (2) generation of solutions; and (3) selection of the best solution. This places the step 1 of the EBM process (building an answerable question) in a (...) pivotal position for the understanding of the whole process, and underscores a few aspects which are often overlooked in EBM courses. First in this step internal evidence (including personal expertise) must be appraised and integrated in the problem. Second, issues of applicability of the possible solution should be anticipated. Third, and possibly more important, the goal of the intervention should be set at this stage (typically by choosing the outcome in a PICO question). Depending whether or not goals depend on the goals of others, and whether they concern others' voluntary behaviour, goals may be classified as self-serving, moral, altruistic or moralistic. Thus, delicate ethical questions must be addressed at this stage, which means that patient preferences and values must be carefully sought, so that empathy, counselling and narrative medicine must be mastered to be able to formulate correctly an answerable question. The need to modify the current description of the EBM process to increase the recognition of implicit assumptions and increase the consistency of this model is discussed. (shrink)

Cooperation and conversation in the public sphere may overcome historical and other barriers to rational argumentation. As an alternative to evidence-based medicine (EBM) and patient-centered care (PCC), the recent development of a modern version of person-centered medicine (PCM) signals an opportunity for a conversational pluralogue to replace parallel monologues between EBM and its critics, and the calls to EBM to debate its critics. This article draws upon elements of Habermas’s theory of communicative action in order to suggest the kind of (...) pluralogue that is required for stakeholders in modern medicine to benefit more from publicly conversing with each other than speaking alone or using debate to argue against each other. This reasoned perspective has lessons for all discourse when deep value-based and epistemological differences cannot be easily adjudicated. (shrink)