Despite more than a decade of bench marking and public reporting of quality problems in the health care sector, changes in medical practice have been slow to materialize. To accelerate quality improvement, many private and public payers have begun to offer financial incentives to physicians and hospitals based oil their performance oil clinical and service quality measures. The authors review the empirical literature oil paying for quality in health care and comparable interventions tit other sectors. They find little evidence to support the effectiveness of paying for quality. The absence of findings for an effect maybe attributable to the small size of the bonuses studied and the fact that payers often accounted for only a fraction of the targeted provider's panel. Even tit nonhealth settings, however,where the international features are more favorable to a positive impact, the literature contains mixed results oil the effectiveness of analogous pay-for-performance schemes.