Volume 41 | Number 6 | December 2006

Abstract List

John Robst


This paper uses a unique database to examine premiums paid by beneficiaries for Medigap supplemental coverage. Average premiums charged by insurers are reported, as well as premiums by enrollee age and gender, and additional policy characteristics. Marginal prices for Medigap benefits are estimated using hedonic price regressions. In addition, the paper considers how additional policy characteristics and geographic differences in the use and cost of medical care affect premiums.

Data Sources/Study Setting

A comprehensive database on premiums paid by beneficiaries for newly issued Medigap policies in the year 2000 along with state‐level characteristics.

Study Design

Hedonic pricing equations are used to estimate implicit prices for Medigap benefits.

Data Collection/Extraction Methods

The Centers for Medicare & Medicaid Services contracted for the creation of a detailed database on Medigap premiums. Data were collected in three stages. First, letters were sent directly to insurers requesting premium data. Second, letters were directly to state insurance commissioner's offices requesting premium data. Last, each state insurance commissioner's office was visited to collect missing data.

Principal Findings

With the exceptions of the part B deductible and drug benefit, Medigap supplemental insurance is priced consistent with the actuarial value of benefits offered under the standardized plans. Premiums vary substantially based on rating method, whether the policy is guaranteed issue, Medigap Select, or explicitly for smokers. Premiums increase with enrollee age, but do not vary between men and women. The relationship between premiums and enrollee age varies across rating methods. Attained‐age policies show the strongest relationship between age and premiums, while community‐rated premiums, by definition, do not vary with age. Medigap supplemental insurance premiums are higher in states with poorer health, greater utilization, and greater managed care penetration.


Despite the high cost, Medigap plans are generally priced in accordance with the actuarial value of benefits. The primary exception is the drug benefit, which appears to be subject to substantial adverse selection. Benefits such as the part B deductible and at‐home recovery benefit offer little value to consumers. Several states require insurers to community rate premiums. Such regulation has important implications for premiums, and research needs to consider the impact of such regulation on the Medigap market.