Research on measures of changes in patient outcomes, that is, patient health status and satisfaction, resulting from specific medical and health interventions. Attributing changes in outcomes to medical care requires distinguishing the effects of care from the effects of the many other factors that influence patients' health and satisfaction. With the elimination of the physician's fiduciary responsibility to the patient, outcomes data is gaining increasing importance for patient advocacy and consumer protection. Outcomes research will also be used in the future by payers to identify potential partners on the basis of good outcomes.