Families of trials: The answers to all our questions?

Many important clinical decisions we make on a daily basis in stroke medici ne are not supported by adequate evidence. This leads to variations in prac tice. If practice influences outcome, this must be regarded as unacceptable since it implies that many patients are receiving sub-optimal treatment. W here the advantages of certain treatment policies over others are only mode rate, large randomised clinical trials provide the most reliable evidence o f effectiveness. However, only a tiny proportion of patients with stroke ar e randomised in trials. Instead, the majority are exposed to treatments all ocated haphazardly, rather than randomly, which serves only to delay the em ergence of evidence concerning the relative merits of alternative treatment approaches. We suggest that we might increase the proportion of patients w ho contribute to advancing our knowledge by developing 'families' of trials . A 'family' would comprise a series of randomised trials into which patien ts with stroke may be enrolled either simultaneously or sequentially into o ne or more of the trials which would share common systems for randomisation and follow-up. Such a system would facilitate large, simple, randomised tr ials, reduce research costs, increase the generalisability of trial results and allow clinicians and patients to contribute to advancing our knowledge whenever they are uncertain about the best treatment. In this article, we discuss the advantages of this approach, some of the problems and their pot ential solutions.