Evidence-Based Medicine (EBM)

“There is also the problem of clinical epidemiology being concerned with groups. I have yet to find a clinical epidemiologist who openly acknowledges the ambiguity of the probability concept. They see in a scientific study that 90 percent of patient were cured, and then they take it for granted that there is a 90 percent chance that Mr. Brown will be cured. But that is an extremely interesting problem. What is a probability of one person being cured? Either he is cured or he is not cured. What if Mr. Brown is very old, and another study has shown that old people in general have a worse prognosis? How do you combine these probabilities? It is extremely complex, but that is what clinical medicine is all about. . . . [Trials] can run you ragged on the trivial” (Hendrik Wulff, in J. Daly, 108, and more generally 103-109).