The assessment of a health practice and the development of a policy for the use of that practice is the final step in a long process that begins with a research idea and ends in actual changes in people's health. All the accumulated research, development, and experience is converted into practical recommendations that largely determine what happens to a patient. In this pivotal position the design of a policy deserves whatever effort is required to ensure that all the proceeding work is put to the best effect1

There is an explosion of interest in guidelines, reflected in a vivid debate ranging from “the best thing since sliced bread” to cries of “cookbook medicine” and fears of constraint on clinical freedom.2 3 4 5 6 7 8 Furthermore, the Department of Health has introduced an initiative to encourage the adoption of evidence based guidelines within purchaser-provider contracts,9 10 and a review of the effectiveness of clinical guidelines has recently been published.11

The subject of guidelines is complex. Even for enthusiasts, ensuring that guidelines are effective by addressing each part of the complex chain of development, dissemination, implementation, and evaluation (fig 1) can be a daunting task. There are an increasing number of publications on the subject--for example, on the details of guideline development and effectiveness.1 12 13 14 15 16 In particular, the seminal work of Grimshaw and Russell has led to a …