The Bell Curve

Thoughts on the impact of statistical analysis on medicine. As Gawande points out, every other business is constantly driving towards these kinds of improvements. Six Sigma, ISO 9001/2, CMM, ITIL, are aimed at making business processes standardized as the first step in improving it. If it can't be measured, it can't be improved.

It used to be assumed that differences among hospitals or doctors in a particular specialty were insignificant. If you plotted a graph showing the results of all the centers treating cystic fibrosis—or any other disease, for that matter—people expected that the curve would look something like a shark fin, with most places clustered around the very best outcomes. But the evidence has begun to indicate otherwise. What you tend to find is a bell curve: a handful of teams with disturbingly poor outcomes for their patients, a handful with remarkably good results, and a great undistinguished middle.

Apparently, in order to fix medicine, we need to do two things: measure ourselves and be more open about what [we] are doing. This meant routinely comparing the performance of doctors and hospitals, looking at everything from complication rates to how often a drug ordered for a patient is delivered
correctly and on time. And, Berwick insisted, hospitals should give patients total access to the information. “‘No secrets’ is the new rule in my escape fire, ”We are used to thinking that a doctor’s ability depends mainly on science and skill. The lesson from Minneapolis is that these may be the easiest parts of care. Even doctors with great knowledge and technical skill can have mediocre results; more nebulous factors like aggressiveness and consistency and ingenuity can matter enormously.

Once we acknowledge that, no matter how much we improve our average, the bell curve isn’t going away, we’re left with all sorts of questions. Will being in the bottom half be used against doctors in lawsuits? Will we be expected to tell our patients how we score? Will our patients leave us? Will those at the bottom be paid less than those at the top? The answer to all these questions is likely yes.