Estimating Medicare Advantage Lock-In Provisions Impacton Vulnerable Medicare Beneficiaries

Beginning January 2006, Medicare ben-eficiaries will have limited ability to changehealth plans. We examine the Medicaremanaged care enrollment and disenroll-ment behavior of traditionally vulnerablebeneficiaries from 1999-2001 to estimatethe potential impact of the new enrollmentrestrictions. Findings that several suchgroups were more likely to make multiplehealth plan elections, leave their managedcare plan midyear, and/or have higher vol-untary disenrollment rates and transfers tooriginal fee-for-service (FFS) Medicaresuggest that the lock-in provisions may havegreater negative impacts on vulnerable ben-eficiaries. This article identifies several rec-ommendations that CMS might consider tolessen the detrimental effects on at-riskgroups.