Medical audit and continuing medical education (CME) are now the mainstays of quality assurance in hospitals. Audits should address problems that have serious consequences for patients if proper treatment is not given. The single most important step is the selection of essential or scientific criteria that relate process to outcomes. CME does less than commonly believed to improve care. Today, quality assurance increasingly means a near-guarantee to every patient of appropriate treatment and fewest possible complications. Maintenance of the public trust rests on a firm commitment of the medical staff and board to this principle, implemented through an organized program of quality assurance. Under these conditions, medical audit and CME can effectively improve care by improving physician performance.