Association between Medicare Advantage plan star ratings and enrollment.

Importance: The US Centers for Medicare & Medicaid Services publishes star ratings reflecting Medicare Advantage plan quality to inform enrollment decisions.

Objective: To assess the association between publicly reported Medicare Advantage plan quality ratings and enrollment.

Design, Setting, And Participants: Cross-sectional study of 2011 Medicare Advantage enrollments among 952,352 first-time enrollees and 322,699 enrollees switching plans.

Main Outcome Measure: Association between star ratings and enrollment was modeled using conditional logit regression, controlling for beneficiary and plan characteristics.

Results: Among the 952,352 included first-time enrollees, a 1-star higher rating was associated with a 9.5 (95% CI, 9.3-9.6) percentage-point increase in likelihood to enroll. The highest rating available to a beneficiary was associated with a 1.9 (95% CI, 1.8-2.1) percentage-point increase in likelihood to enroll. Among the 322,699 enrollees switching plans, a 1-star higher rating was associated with a 4.4 (95% CI, 4.2-4.7) percentage-point increase in likelihood to enroll. A rating at least as high as a beneficiary's prior plan was associated with a 6.3 (95% CI, 6.0-6.6) percentage-point increase in likelihood to enroll. Star ratings were less strongly associated with enrollment for black, rural, low-income, and the youngest beneficiaries.

Conclusion And Relevance: Medicare's 5-star rating program for Medicare Advantage is associated with beneficiaries' enrollment decisions.