Describes a UK project to implement randomised trials as unobtrusively as possible in the everyday clinical work of general practitioners (GPs), comparing treatments that are already in common use, and using routinely collected electronic healthcare records (EHR) both to identify participants and to gather results.  The authors discuss the rationale for this approach, the potential for improving clinical evidence at low cost, and the barriers encountered.

Authors conclude that 'EHR databases contain a wealth of information, and their utility for randomised evaluations should be fully exploited.  A revolution is long overdue in the technical and research governance frameworks for testing widely used interventions whose relative merits are unknown.  Narrowly restricted studies with questionable external validity need not be the norm.  Our suggestion for large scale randomisation in usual clinical practice may face several challenges, some of them technical, but most of them related to research governance procedures.  We hope that these barriers will be overcome, by providing proof of concept for a streamlined simple framework for undertaking REACT trials, in which recognition of widespread uncertainties about the effects of treatments will motivate clinicians and patients to participate in randomised evaluations as a matter of routine.'