Stephanie Shimada

Stephanie Shimada

Research Health Scientist, Center for Healthcare Organization and Implementation Research, Bedford VA Medical Center
Research Assistant Professor, Department of Health Law, Policy, and Management, Boston University School of Public Health

Dissertation Title:  "Selection in the Medicare Program"

This dissertation uses data from the Medicare Managed Care and Fee For Service versions of the Consumer Assessments of Health Plans Study (CAHPS) surveys to examine market, plan, and individual characteristics that drive selection into Medicare managed care.

The first paper examines selection into Medicare managed care (MMC) based on beneficiary characteristics such as health status, education, and race and then explores the association between market characteristics and favorable health-based selection into MMC. Results showed that although MMC plans continued to experience favorable selection on health, this effect diminished in areas with higher MMC penetration, more MMC options, and more competition among plans. Ethnic minorities were more likely to be enrolled in MMC than whites. The strongest predictor of enrollment in Medicare managed care was low educational attainment. The effect of educational attainment was even more pronounced among healthy beneficiaries. Medicare patients’ ratings and reports of the quality of their health care, as assessed by CAHPS surveys, are generally lower for sicker beneficiaries than for healthy beneficiaries.

The second paper examines this ‘quality gap’ between sick and healthy beneficiaries’ CAHPS scores and explores its association with biased selection into Medicare managed care. The results show a significant association between the quality gap and several CAHPS composites. Areas with a large quality gaps in patient-provider communication tend to have fewer sick beneficiaries enrolled in Medicare managed care. Areas with large quality gaps in the quality domains assessed by the “Getting Needed Care” and “Getting Care Quickly” composites tend to have more sick beneficiaries enrolled in Medicare managed care plans.

The third paper explores the choices of Medicare beneficiaries who were involuntarily disenrolled from their Medicare managed care plans to gain an understanding of the effects of market, plan, and individual characteristics on subsequent choice of coverage. Involuntarily disenrolled beneficiaries were less likely to return to traditional Medicare in states with higher Medigap rates. Those who chose to remain in a Medicare managed care plan were more likely to enroll in plans with lower premiums, lower copayment rates for doctor and specialist visits, and higher CAHPS scores.


Graduation Year