Stories are a good way to communicate and many anecdotes become data. These and other potentially heretical statements were discussed at the recent Third International Conference on the Scientific Basis of Health Services in Toronto. Controversy reigns with respect to mammography screening guidelines for women in their 40s, an issue with which I have been intimately involved as a researcher. The guidelines are not consistent, and for the most part, neither women nor physicians have complied with them. This conference addressed the question, explored the many factors involved and demonstrated that there is still much to learn.
Evidence is more than numbers obtained from methodologically rigorous scientific research.
Evidence comes also from experience and evidence will always be modified by values. What is good to one sector of society may not be to another. Well, yes they have, but the problem in a nutshell becomes what do we mean by evidence and where do we get it from. Obviously physicians will never be able to get all their evidence from randomized, controlled trials. Experience shows us the results of such trials almost invariably induce a backlash.