I would hesitate to interpret this so naively. For example, there are some vascular surgeons who take on patients that nobody else will touch. These are patient

I would hesitate to interpret this so naively. For example, there are some vascular surgeons who take on patients that nobody else will touch. These are patients with many bad prognostic risk factors, but they will die without the surgery. The surgeons who take these patients may end up having terrible stats, but be the most skilled if only because their mortality rate is not pushing 100%. Comparing this statistic the way people compare gas mileage is a disincentive for these surgeons to operate on patients that need help, but are high risk.