The evolution of clinical policies.

Physicians use clinical policies as guidelines in the day-to-day management of patients. Some policies, by reducing otherwise complicated dilemmas to simple rules, encourage improved patient outcomes, but some are adopted without any evidence of benefit; some may be extended beyond their proper limitations and others are used despite accumulating data that they are at best useless and at worst dangerous. Four stages, development, diffusion, domination, and disillusionment, may be recognized in the evolution of clinical policies. Social rather than scientific forces play a central role, and at each step characteristic errors in both reasoning and research may occur. Attempts to improve patient outcomes by encouraging more appropriate research methodology and increasing the ability of physicians to critically appraise published studies may not be successful unless account is also taken of the social forces that influence the use and abuse of clinical policies.