Evidence seems to change frequently

EDITOR—Freeman and Sweeney's study on why general practitioners do not implement evidence seems to share the underlying assumption of so much that is written on this subject—that evidence is clear cut, and the only problem is getting practitioners to put it into practice.1 My perception of evidence, however, is that it is often slippery—at best frequently changing and at worst contradictory and confusing—and that best evidence is often not very good. Part of the problem is therefore deciding exactly what to put into practice.

The findings and interpretation of individual papers, systematic reviews, meta-analyses, and reviews of systematic reviews and meta-analyses are regularly debated in the BMJ. Anticoagulation was one of the clinical areas discussed by the participants in Freeman and Sweeney's study, but stroke prevention in atrial …