Effects of pay for performance on the quality of primary care in England

BACKGROUND: A pay-for-performance scheme based on meeting targets for the quality of clinical care was introduced to family practice in England in 2004. METHODS: We conducted an interrupted time-series analysis of the quality of care in 42 representative family practices, with data collected at two time points before implementation of the scheme (1998 and 2003) and at two time points after implementation (2005 and 2007). At each time point, data on the care of patients with asthma, diabetes, or coronary heart disease were extracted from medical records; data on patients' perceptions of access to care, continuity of care, and interpersonal aspects of care were collected from questionnaires. The analysis included aspects of care that were and those that were not associated with incentives. RESULTS: Between 2003 and 2005, the rate of improvement in the quality of care increased for asthma and diabetes (P