The case for case-mix adjustment in practice profiling. When good apples look bad.

Abstract

Failure to adjust for case mix in physician practice profiles may lead to overestimates of variation and misidentification of outliers. To the extent that unadjusted practice profiles are used for decisions about education, sanctions, or employment, physicians may be subject to inequitable decisions and actions. Misinformation about the causes and extent of practice variation may also lead to misdirection of scarce resources for quality improvement efforts.