The paradigm of modern quality management is in wide use in health care. Although much of the initial effort in health care has focused on improving service, administrative, and support processes, many organizations are also using these concepts to improve clinical care. The analysis of data on clinical outcomes has undoubtedly led to many local improvements, but such analysis is inevitably limited by three issues: small samples, lack of detailed knowledge of what others are doing, and paradigm paralysis. These issues can be partially overcome when multiple health care organizations work together on focused clinical quality improvement efforts. Through the use of multiorganizational collaborative groups, literature reviews, expert panels, best-practice conferences, multiorganizational databases, and bench-marking groups, organizations can effectively pool data and learn from the many natural experiments constantly underway in the health care community. This article outlines the key concepts behind such collaborative improvement efforts and describes pioneering work in the application of these techniques in health care. A better understanding and wider use of collaborative improvement efforts may lead to dramatic breakthroughs in clinical outcomes in the coming years.