Determinants of the Percent of the Population Enrolled in HMOs

This study endeavors to identify key factors influencing interstate differentials in the percentage of the population enrolled in HMOs. Among other things, the cross-section analysis finds the percentage of a state’s population enrolled in HMOs to be a decreasing function of the state’s unemployment rate, the percent of the state’s population at or below the poverty level, and the percentage of the population in the state that filed a federal personal income tax return that included a Schedule C (as a proxy for self employment and independent contractors). In addition, the study finds the percentage of a state’s population enrolled in HMOs to be an increasing function of the percentage of the state’s labor force that is unionized and the state’s female labor force participation rate. The analysis also considers as additional explanatory variables the percent of the population that is black, the percent of the population that is Hispanic, and median family income. These variables do not appear to play a significant role in explaining HMO enrollments.