Volume 39 | Number 4p1 | August 2004

Abstract List

Adam Atherly Ph.D., Bryan E. Dowd Ph.D.,, Roger Feldman Ph.D.


To estimate the effect of Medicare+Choice (M+C) plan premiums and benefits and individual beneficiary characteristics on the probability of enrollment in a Medicare+Choice plan.

Data Source

Individual data from the Medicare Current Beneficiary Survey were combined with plan‐level data from Medicare Compare.

Study Design

Health plan choices, including the Medicare+Choice/Fee‐for‐Service decision and the choice of plan within the M+C sector, were modeled using limited information maximum likelihood nested logit.

Principal Findings

Premiums have a significant effect on plan selection, with an estimated out‐of‐pocket premium elasticity of −0.134 and an insurer‐perspective elasticity of −4.57. Beneficiaries are responsive to plan characteristics, with prescription drug benefits having the largest marginal effect. Sicker beneficiaries were more likely to choose plans with drug benefits and diabetics were more likely to pick plans with vision coverage.


Plan characteristics significantly impact beneficiaries' decisions to enroll in Medicare M+C plans and individuals sort themselves systematically into plans based on individual characteristics.