Decision making in medicine and health care.

Decision making is central to health policy and medical practice. Because health outcomes are probabilistic, most decisions are made under conditions of uncertainty. This review considers two classes of decisions in health care: decisions made by providers on behalf of patients, and shared decisions between patients and providers. Considerable evidence suggests wide regional variation exists in services received by patients. Evidence-based guidelines that incorporate quality of life and patient preferences may help address this problem. Systematic cost-effectiveness analysis can be used to improve resource allocation decisions. Shared medical decision making seeks to engage patients and providers in a collaborative process to choose clinical options that reflect patient preferences. Although some evidence indicates patients want an active role in making decisions, other evidence suggests that some patients prefer a passive role. Decision aids hold promise for improving individual decisions, but there are still few systematic evaluations of these aids. Several directions for future research are offered.