One of the common ingredients in all attempts to slow escalating health care costs is to control the utilization of services that provide little or uncertain benefit. To reform existing delivery systems, the organization, provision, and financing of health care need to be evaluated critically. Successful reform requires that more rational methods be used to determine which services to provide. The preferences of physicians, patients, and payers of care do not appear optimal from a societal perspective in choosing health care services. While reducing the use of interventions of little or unknown benefit should save money, a policy to restrict the use of medical services may lead to an unwanted result: the underutilization of interventions of proven clinical benefit. Through the determination of the value—by rigorous assessment of both costs and benefits of available alternatives—in a context sensitive to the unique cultural, political, and economic characteristics of individual nations, the health of the population should be improved and growth of health expenditures constrained. This is the first step in health care reform.