August 30, 2005
Edward Tufte, quoting Dr. E. E. Peacock, Jr., tells a lovely little story to remind us that good statistical analysis is always about comparisons:
One day when I was a junior medical student, a very important Boston surgeon visited the school and delivered a great treatise on a large number of patients who had undergone successful operations for vascular reconstruction. At the end of the lecture, a young student at the back of the room timidly asked, "Do you have any controls?" Well, the great surgeon drew himself up to his full height, hit the desk, and said, "Do you mean did I not operate on half of the patients?" The hall grew very quiet then. The voice at the back of the room very hesitantly replied, "Yes, that's what I had in mind." Then the visitor's fist really came down as he thundered, "Of course not. That would have doomed half of them to their deaths." God, it was quiet then, and one could scarcely hear the small voice ask, "Which half?"
And then there's this: "Most Scientific Papers Are Probably Wrong". (Well-known in social sciences, even if it's big news to the media.)