What is the effect of pay for performance on hospitals that serve poor patients?

KEY FINDINGS: (1) After three years of participation in a CMS pay-for-performance initiative, hospitals that served a high number of poor patients realized gains in quality improvement measures on certain clinical conditions. (2) The gains among these hospitals were greater than gains among other hospitals, allowing them to close the gaps seen prior to the onset of pay for performance. (3) Hospitals that served a high number of poor patients started with lower baseline quality performance than other hospitals.