To inform enrollment decisions and foster improvement in Medicare Advantage plans, the Centers for Medicare & Medicaid Services publishes star ratings, which are based on administrative and consumer data and intended to reflect plan quality. However, whether such quality ratings influence plan enrollment patterns among beneficiaries is not clear. In a cross-sectional study of 2011 Medicare Advantage enrollments (952 353 first-time enrollees and 322 699 enrollees switching plans), Reid and colleagues assessed the association between star ratings and plan enrollment. In analyses that controlled for beneficiary and plan characteristics, the authors found that higher star ratings were associated with increased likelihood of plan enrollment among both first-time enrollees and those switching plans. In an editorial, Hoadley discusses health plan performance ratings and consumers' choice among competing plans.