Effects of HMO Market Structure on Firm and Consumer Behavior in the Employment-Based Health Insurance Market. Abstract, Executive Summary and Final Report

摘要

This report presents the results of a number of multivariate statistical analysesthat address the general question of how variations in HMO market structure affect particular aspects of the employment-based health insurance market. HMO market structure is measured by two variables defined for sample employers in metropolitan statistical areas (MSAs): HMO penetration (HMO enrollment as a percentage of total population) is a continuous measure of the prevalence of HMOs in the market: and HMO competition, which indicated whether the market has both high HMO penetration (30 percent or higher) and high HMO competition (in the first quartile of the Hirschman-Herindahl Index of HMO concentration). The particular dependent variables analyzed are: (1) the type of insurance plan offered by employers; (2) premiums charged to employers for managed care and fee-for-service plans; (3) premium sharing between employers and workers; (4) the use of internal financial incentives by employers to influence workers' selection of an insurance plan; and (5) the effects of such incentives and HMO market structure on the proportion of workers actually selecting a managed care plan.