Notes on Certainty

Dr. Freedman, who has written books on the science and history of clinical trials, says he is reminded of a story about a pioneer in the medical application of statistics, Pierre-Charles-Alexandre Louis.

In the 1830s, Dr. Louis studied the effect of bloodletting, or bleeding—the standard treatment of the time—on pneumonia.

“The data showed that bleeding didn’t work,” Dr. Freedman said. But, he said, “Dr. Louis rejected this as terrifying and absurd.”

So, he made a recommendation: bleed earlier and bleed harder.

Gina Kolata