To the Editor.
—The development of clinical policies is important to patient care, health policy, legal standards, clinical research, and professional education. Many professional organizations are now involved in the development of such policies, calling them by a wide variety of names and using a broad range of methods. The American Medical Association recently compiled a list of more than 1500 policies, parameters, and guidelines. President Clinton has made the development and implementation of clinical policies central elements of his administration's program for health system reform.If a policy is to change clinical behavior, it must be credible to the practicing physician. The method pioneered by Eddy1 makes major advances by basing clinical policies on the explicit examination of benefits, risks, costs, outcomes, and patient preferences. Credibility, however, will require that one additional element of the policy process be made explicit: the sources of support. Clinical policies will have