Research in resource allocation in a prepaid group practice.

Much that has been written about the concept, operation, and performance of HMOs--their use of resources compared with other health service systems--masks the real differences among HMOs themselves. Investigation of autonomous units within a unified HMO program shows a surprising diversity. Analytic formulations drawn from long-term and large-scale research fail to account for variations in staffing, budgeting, rate setting, and expansion when applied to institutional research. Judgment of intangibles remains a key aspect of most major decisions.