Better data on the quality of health care being delivered in the United States are urgently needed if efforts to reform the nation's health care system are to succeed. This paper describes a "distributed data approach" to computing performance results while protecting patients' privacy. The strategy builds on the efforts of the Quality Alliance Steering Committee, a multistakeholder coalition focused on the implementation of performance measures. Instead of waiting for the government or the private sector to build large data warehouses, existing data from administrative sources, laboratories, clinical registries, and electronic health records could be put to greater use now, resulting in improved patient care and spurring further advances in performance measurement. In this article we introduce an overall framework for achieving these goals, and we describe a set of steps to accelerate and expand the availability of performance measures to improve care now.