The Joint Commission on Accreditation of Healthcare Organizations, the oldest health care accrediting body in the world, currently accredits almost 20 000 organizations in the USA. Although continuing to be professionally-sponsored, accreditation's rapid growth in recent years has been driven by the external users of accreditation – government, purchasers, and publi – rather than by the original users, the professionals themselves. This experience in the USA suggests that over time successful external quality evaluation mechanisms throughout the world will involve representatives of the public, purchasers, and government in establishing standards and setting policies. Without this involvement, these stakeholders are unlikely to find the mechanisms credible in addressing their needs, and will seek alternatives – adding cost and duplication to the external quality evaluation system. Successful mechanisms are also likely to provide more detailed information about an organization's performance to the public, purchasers, and the government, while creating evaluation processes that provide for innovation and support improvement in efficiency, as well as quality, through incorporation of aspects of the Baldrige and European Foundation for Quality Management approaches to organizational excellence. Finally, successful evaluation mechanisms are likely to create a special focus on the safety of care, incorporating aspects of the International Organization for Standardization's ISO 9000 approach to quality management. While the specific nature, priority, and timing of these changes will differ from country to country, they are likely to influence the evolution of external quality evaluation throughout the world. External evaluation of health care organizations» quality holds great promise, but its long-term success depends on responding to all those who will want to depend on it.