The Bell Curve
What happens when patients find out how good their doctors really are?
It used to be assumed that differences among hospitals or doctors in a particular specialty were generally 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.
In ordinary hernia operations, the chances of recurrence are one in ten for surgeons at the unhappy end of the spectrum, one in twenty for those in the middle majority, and under one in five hundred for a handful. A Scottish study of patients with treatable colon cancer found that the ten-year survival rate ranged from a high of sixty-three per cent to a low of twenty per cent, depending on the surgeon. For heartbypass patients, even at hospitals with a good volume of experience, risk-adjusted death rates in New York vary from five per cent to under one per cent—and only a very few hospitals are down near the one-per-cent mortality rate.
It is distressing for doctors to have to acknowledge the bell curve. It belies the promise that we make to patients who become seriously ill: that they can count on the medical system to give them their very best chance at life. It also contradicts the belief nearly all of us have that we are doing our job as well as it can be done. But evidence of the bell curve is starting to trickle out, to doctors and patients alike, and we are only beginning to find out what happens when it does.