HMO plan performance update: an analysis of the literature, 1997-2001.

This paper synthesizes results from peer-reviewed literature published from 1997 to mid-2001, on various dimensions of health maintenance organization (HMO) plan performance. Results from seventy-nine studies suggest that both types of plans provide roughly comparable quality of care, while HMOs lower use of hospital and other expensive resources somewhat. At the same time, HMO enrollees report worse results on many measures of access to care and lower levels of satisfaction, compared with non-HMO enrollees. Quality-of-care results in particular are heterogeneous, which suggests that quality is not uniform--that it varies widely among providers, plans (HMO and non-HMO), and geographic areas.