Choices in health care delivery must be made at two levels: (1) the individual physician prescribing a course of treatment for an individual patient and (2) the policy maker determining the availability of medical care to an entire group of patients or a community. One way to choose among alternative treatment regimens and community programs is by using the criterion of economic efficiency. Briefly describe the three types of appraisal that enter into medical economics. Discuss the unique features of each, and describe their basic strengths and weaknesses.