Why evidence-based medicine?

This chapter considers briefly what counts as ‘evidence’ and describes three historical strands, in medical science generally, in epidemiology and in clinical trials, that have converged to give rise to the concept of evidence-based medicine. It then returns to the randomized controlled trial as the fundamental building block of evidence-based practice. Finally, through considering whether all trials are equally useful, it demonstrates that discerning what is the best way to proceed in the clinical management of individual patients and problems is not necessarily a simple matter.