Physician need. An alternative projection from a study of large, prepaid group practices.

To model a base level of physician demand in a managed health care system, we examined in 1983 the ratios by specialty of full-time equivalent physicians to health maintenance organization members in seven large, closed-panel health maintenance organizations, each with more than 100,000 members. The medical director of each plan was surveyed by mailed questionnaire and telephone interview to determine the plan's number of full-time equivalent physicians by specialty and members served. Out-of-plan physicians contracted by the group were included within the specialty distribution wherever possible. We compared our findings (4779.4 full-time equivalent physicians serving 4,297,790 members) with Graduate Medical Education National Advisory Committee and others' projections of physician need and supply. Based on this model and unknowns that might affect utilization, our study suggests that at least 111 physicians per 100,000 population would be necessary in a system that emphasized reduced utilization of services and that more primary care physicians would be needed than the Graduate Medical Education National Advisory Committee predicted would be available.