[HelloMcFly]

This is also pretty much the easiest thing the factor out through mixed effects modeling (among other methods if required). But your statement that higher scoring physicians go to places with healthier patient populations is not correct across all disciplines. Often it can be the opposite: the best physicians go to the major hospitals (usually but not always university affiliated) located in major population centers that draw in the sickest/worst/rarest cases from the surrounding geography.