Three broad movements are seeking to change the world of medicine. The proponents of 'evidence-based medicine' are mainly concerned with ensuring that strategies of proven clinical effectiveness are adopted. Health economists are mainly concerned to establish that 'cost-effectiveness' and not 'clinical effectiveness' is the criterion used in determining option selection. A variety of patient support and public interest groups, including many health economists, are mainly concerned with ensuring that patient and public preferences drive clinical and policy decisions. This paper argues that decision analysis based medical decision making (DABMDM) constitutes the pre-requisite for the widespread introduction of the main principles embodied in evidence-based medicine, cost-effective medicine and preference-driven medicine; that, in the light of current modes of practice, seeking to promote these principles without a prior or simultaneous move to DABMDM is equivalent to asking the cart to move without the horse; and that in fact DABMDM subsumes and enjoins the valuable aspects of all three. Particular attention is paid to differentiating between DABMDM and EBM, by way of analysis of various expositions of EBM and examination of two recent empirical studies. EBM, as so far expounded, reflects a problem-solving attitude that results in a heavy concentration on RCTs and meta-analyses, rather than a broad decision making focus that concentrates on meeting all the requirements of a good clinical decision. The latter include: ensuring that inferences from RCTs and meta-analyses to individual patients (or patient groups) are made explicitly; paying equally serious attention to evidence on values and costs as to clinical evidence; and accepting the inadequacy of 'taking into account and bearing in mind' as a way of integrating the multiple and distinct elements of a decision.