Clinical policies, also known as practice parameters or practice guidelines, are gaining notoriety out of a desire to control escalating medical costs, lessen wide practice variations, and improve quality of care. The clinical policies are supposed to influence medical decision making by summarizing scientific data about a clinical problem in a format that is easily understood by patient and physician alike. Developing an evidence-based policy involves: a clearly defined clinical problem, a comprehensive literature review, a summary table of the data (known as an evidence table), a presentation of this data as outcome possibilities from alternative decisions (in the form of a balance sheet), and creation of clinical recommendations that incorporate both financial costs and patient preferences. Well-developed policies can be used by family physicians as guides in areas of clinical uncertainty and by medical educators as up-to-date literature syntheses for teaching critical appraisal and for outlining approaches to common problems. Explicit policy formulation also highlights the shortcomings of existing literature and can suggest more appropriate future research. The future of the clinical policy movement rests on its ability to reduce costs of care and improve patient outcomes. Explicit clinical policy formulation incurs significant development and implementation costs and the evidence on which many policies are based is lacking. Nevertheless, clinical policies in some form are likely to play an increasing role in medical care.