Thirty years ago, the practice of medicine began a radical change of direction. As the pace of therapeutic discovery slowed in the late 1980s, many came to believe that the greatest benefit in the future might come not from innovative breakthroughs, but by the more consistent application of existing knowledge.1 If best practice could be identified by evidence from randomized clinical trials in a systematic way, and presented to clinicians as a set of recommendations, the general level of practice could be improved and assessed by objective criteria. Evidence-based medicine (EBM) became the accepted engine for medical progress, with systematic reviews and guidelines as the chosen instruments for promoting better and more standardized practice.2