Evidence-based medicine is a slogan. Randomized, controlled trials based on homogeneous groups in contrived settings don't tell you much about what works in the real world.
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.