Introduction

Stories of clinical innovation in medicine are generally stories of fits and starts, of irrational exuberance and of avoidable tragedy, of skill, luck, science, and serendipity. Such stories are often transformed, in retrospect, into orderly, semi-fictional narratives that show science as a rational process. These narratives portray medical progress as the result of carefully designed experiments that test specific hypotheses. The results of such experiments, so the story goes, are then incorporated into clinical practice. The real history of innovation is both more fun and more frightening than such myths might suggest.

In the real world, progress is non-linear and messy because every innovation is a frightening gamble. When innovations are first tried, we know little about them. We don’t know whether they will work, for whom, or with what associated harms. We don’t know whether the benefits will ultimately outweigh the risks. We don’t know the comparative effectiveness of innovative and standard therapies. We aren’t even sure exactly when it is ethically permissible to study a new therapy, or which research methodology is best, or when it has been studied enough. Even when good studies are done, it is often hard to interpret the results.