A conceptual model of the effects of health care organizations on the quality of medical care.

There has been a great deal of interest in recent years in developing measures of health care quality that can be used to characterize and study the effects of health plans. However, because of the recent emergence of diverse types of health care organizations, it is often difficult to know which parts of a plan should be combined for analysis purposes. Also, simple taxonomies of health maintenance organizations (eg, staff, independent practice associations, group, and network) no longer adequately describe the diverse types of organizations that have become common. In this article we describe these trends, explain why older taxonomies of health care plans are not adequate, and present a new framework for characterizing and studying the effects of diverse types of plans.