The evidence on evidence-based medicine speaks for itself. The approach is a vast improvement over everything that came before, and over current rival approaches. It’s often enough to give its practitioners a bit of hubris –which is why it’s so important to remember that evidence-based medicine can’t tell us everything we want to know, either. Possible pitfalls and limitations of evidence-based medicine were on stark display at a press conference of the American Society of Hematology last week, where not one, but two studies reported results that were the opposite of what one might suspect from looking at one part...