RESUMEN
In 2014, the Affordable Care Act (ACA) expanded the role of Medicaid by encouraging states to increase eligibility for lower-income adults. As of 2024, 10 states had not adopted the expanded eligibility provisions of the ACA, possibly due to concerns about the state's share of spending. Using the Medical Expenditure Panel Survey (MEPS), we documented how health care utilization, expenditures, and the overall health status of newly eligible enrollees compare with enrollees who would have been eligible under their states' rules before the ACA. Our estimates suggest that, during 2014-16, newly eligible Medicaid enrollees had worse health and greater utilization and expenditures than previously eligible enrollees. However, during 2017-19, newly and previously eligible enrollees had comparable per capita health expenditures across six types of health spending. We find some evidence that changes in Medicaid enrollment composition muted observed differences between eligibility groups.
Asunto(s)
Determinación de la Elegibilidad , Gastos en Salud , Medicaid , Patient Protection and Affordable Care Act , Humanos , Medicaid/estadística & datos numéricos , Medicaid/economía , Estados Unidos , Gastos en Salud/estadística & datos numéricos , Adulto , Femenino , Masculino , Persona de Mediana Edad , Adulto Joven , Pobreza/estadística & datos numéricos , Aceptación de la Atención de Salud/estadística & datos numéricos , Estado de Salud , AdolescenteRESUMEN
There is widespread agreement that taxpayers pay more when Medicare beneficiaries are enrolled in Medicare Advantage (MA) plans than if those beneficiaries were enrolled in traditional Medicare. MA plans are paid on the basis of submitted diagnoses and thus have a clear incentive to encourage providers to find and report as many diagnoses for their enrollees as possible. Two mechanisms that MA plans use to identify diagnoses that are not available for beneficiaries in traditional Medicare are in-home health risk assessments and chart reviews. Using MA encounter data for 2015-20, I isolated the impact of these two types of encounters on the risk scores used for payments to MA plans during 2016-21. I found that encounter-based risk scores for MA enrollees were higher by 0.091 points, or 7.4 percent, in 2021 when in-home health risk assessments and chart reviews were included than they would have been without the use of these tools.
Asunto(s)
Medicare Part C , Humanos , Estados Unidos , Medición de Riesgo , Anciano , Masculino , Femenino , Anciano de 80 o más Años , Codificación Clínica , Servicios de Atención de Salud a Domicilio/economíaRESUMEN
The United States offers two markedly different subsidy structures for private health insurance. When covered through employer-based plans, employees and their dependents benefit from the exclusion from taxable income of the premiums. Individuals without access to employer coverage may obtain subsidies for Marketplace coverage. This paper seeks to understand how the public subsidies embedded in the privately financed portion of the U.S. healthcare system impact the payments families are required to make under both ESI and Marketplace coverage, and the implications for finance equity. Using the Household Component of the Medical Expenditure Panel Survey (MEPS-HC) and Marketplace premium data, we assess horizontal and vertical equity by calculating public subsidies for and expected family spending under each coverage source and using Lorenz curves and Gini and concentration coefficients. Our study pooled the 2018 and 2019 MEPS-HC to achieve a sample size of 10,593 observations. Our simulations showed a marked horizontal inequity for lower-income families with access to employer coverage who cannot obtain Marketplace subsidies. Relative to both the financing of employer coverage and earlier Marketplace tax credits, the more generous Marketplace premium subsidies, first made available in 2021 under the American Rescue Plan Act, substantially increased the vertical equity of Marketplace financing. While Marketplace subsidies have clearly improved equity within the United States, we conclude with a comparison to other OECD countries highlighting the persistence of inequities in the U.S. stemming from its noteworthy reliance on employer-based private health insurance.
Asunto(s)
Seguro de Salud , Humanos , Estados Unidos , Seguro de Salud/economía , Seguro de Salud/estadística & datos numéricos , Financiación Gubernamental/estadística & datos numéricos , Financiación Gubernamental/economía , Cobertura del Seguro/estadística & datos numéricos , Cobertura del Seguro/economía , Intercambios de Seguro Médico/economía , Intercambios de Seguro Médico/estadística & datos numéricos , Sector Privado/economía , Sector Privado/estadística & datos numéricos , Planes de Asistencia Médica para Empleados/economía , Planes de Asistencia Médica para Empleados/estadística & datos numéricosRESUMEN
OBJECTIVES: Families with incomes above 400% of the federal poverty level were ineligible for marketplace premium tax credits before 2021 and may again be after 2025. Current laws temporarily removed this income cap, but because credits cap out-of-pocket premiums for a reference plan as a share of income, some higher-income families still receive zero tax credits. We quantified (1) premium differences between on- and off-marketplace plans and (2) the association between these premium differences and state decisions to finance cost-sharing reductions (CSRs) for lower-income families. STUDY DESIGN: We created a comprehensive database of on- and off-marketplace plans in each county (including both federal and state-based marketplaces). METHODS: By county and metal level, we compared on- and off-marketplace (1) plan premiums in 2020 and (2) growth rates in the numbers of plans. We contrasted outcomes for states by how insurers were instructed to finance CSRs. RESULTS: In 2020, 89% of the US population lived in counties where some plans were offered exclusively off-marketplace. In these counties, for a 45-year-old choosing among silver plans in 2020 and who did not qualify for premium subsidies, premiums for the lowest-cost off-marketplace plans averaged 11.3% less than premiums for the lowest-cost on-marketplace plans. In contrast, for bronze and gold plans, the lowest-cost off-marketplace plans were, on average, more expensive. Silver plan premiums were 6.1% higher off-marketplace than on-marketplace in states that loaded CSRs on all silver plans, and 13.5% lower in states that loaded CSRs only on on-marketplace silver plans. CONCLUSIONS: Higher-income individuals and families may consider purchasing Affordable Care Act-compliant silver plans off-marketplace and thereby reduce their premiums. State and federal policy makers should consider the impact of their decisions on the choice between on- and off-marketplace plans.
Asunto(s)
Intercambios de Seguro Médico , Patient Protection and Affordable Care Act , Estados Unidos , Humanos , Persona de Mediana Edad , Plata , Renta , Seguro de Costos Compartidos , Cobertura del Seguro , Seguro de SaludRESUMEN
The COVID-19 pandemic had the potential to alter patterns of health insurance coverage in the US. Using data from the Medical Expenditure Panel Survey, we found increased stability of Medicaid coverage for children and nonelderly adults during the first year of the pandemic. Fewer people who had Medicaid in 2019 became uninsured in 2020 (4.3 percent) than in 2018-19 (7.8 percent).
Asunto(s)
COVID-19 , Seguro de Salud , Adulto , Niño , Estados Unidos , Humanos , Pandemias , Medicaid , Pacientes no Asegurados , Cobertura del SeguroRESUMEN
Use of recommended preventive care services in the United States is not universal and varies considerably by socio-economic status. We examine whether widespread eligibility for Medicare at age 65 narrows disparate preventive service use by race and ethnicity. Using data across 12 cycles of the Household Component of the Medical Expenditure Panel Survey (2005-2016), we employ a regression discontinuity design to assess changes in the use of preventive services. Our sample included: 8847 Hispanic respondents, 9908 non-Hispanic Black respondents, and 29,527 non-Hispanic White respondents. We examined six preventive services: routine check-ups, blood cholesterol screenings, receipt of the influenza vaccine, blood pressure screenings, mammograms, and colorectal cancer screenings. For non-Hispanic Black adults, we found that preventive service use increased after age 65 across a range of measures including a 4.8 percentage-point (95% confidence interval (CI)1.4, 8.2) increase in blood cholesterol screening, and a 9.1 percentage-point (95% CI 2.1, 15.9) increase in mammograms for Black women. For all four preventive health measures that were lower for Hispanic adults compared with non-Hispanic White adults prior to age 65, service use was indistinguishable (p > 0.10) between these groups after reaching the Medicare eligibility age. Medicare eligibility appeared to reduce most racial and ethnic disparities in preventive service use.
Asunto(s)
Etnicidad , Medicare , Adulto , Anciano , Población Negra , Femenino , Disparidades en Atención de Salud , Hispánicos o Latinos , Humanos , Servicios Preventivos de Salud , Estados UnidosRESUMEN
The Affordable Care Act provides tax credits for Marketplace insurance, but before 2021, families with incomes above four times the federal poverty level did not qualify for tax credits and could face substantial financial burdens when purchasing coverage. As a measure of affordability, we calculated potential Marketplace premiums as a percentage of family income among families with incomes of 401-600 percent of poverty. In 2015 half of this middle-class population would have paid at least 7.7 percent of their income for the lowest-cost bronze plan; in 2019 they would have paid at least 11.3 percent of their income. By 2019 half of the near-elderly ages 55-64 would have paid at least 18.9 percent of their income for the lowest-cost bronze plan in their area. The American Rescue Plan Act temporarily expanded tax credit eligibility for 2021 and 2022, but our results suggest that families with incomes of 401-600 percent of poverty will again face substantial financial burdens after the temporary subsidies expire.
Asunto(s)
Intercambios de Seguro Médico , Patient Protection and Affordable Care Act , Anciano , Costos y Análisis de Costo , Determinación de la Elegibilidad , Humanos , Cobertura del Seguro , Seguro de Salud , Persona de Mediana Edad , Estados UnidosRESUMEN
Medicare pays for roughly one in four physician visits in the United States, yet a rigorous understanding of how Medicare currently affects access to and affordability of care for its enrollees is unavailable. Using data from the Medical Expenditure Panel Survey-Household Component and the National Health Interview Survey, I tested for changes in access to care and affordability around age sixty-five, when most people gain eligibility for Medicare. I found that Medicare eligibility is associated with a 1.5-percentage-point reduction in reports of being unable to get necessary care (a 50.9 percent reduction compared with the percentage at age sixty-four) and a 4.1-percentage-point (45.3 percent) reduction in not being able to get needed care because of the cost. Recently, policy makers have proposed various ways of extending Medicare coverage. These results suggest that incremental Medicare expansions could have positive access and affordability benefits for enrollees compared with the insurance options available to them before they turn sixty-five.
Asunto(s)
Gastos en Salud , Medicare , Anciano , Costos y Análisis de Costo , Atención a la Salud , Determinación de la Elegibilidad , Humanos , Cobertura del Seguro , Estados UnidosRESUMEN
OBJECTIVE: To assess how beneficiary premiums, expected out-of-pocket costs, and plan finances in the Medicare Advantage (MA) market are related to coding intensity. DATA SOURCES/STUDY SETTING: MA plan characteristics and administrative records from the Centers for Medicare and Medicaid Services (CMS) for the sample of beneficiaries enrolled in both MA and Part D between 2008 and 2015. Medicare claims and drug utilization data for Traditional Medicare (TM) beneficiaries were used to calibrate an independent measure of health risk. STUDY DESIGN: Coding intensity was measured by comparing the CMS risk score for each MA contract with a contract level risk score developed using prescription drug data. We conducted regressions of plan outcomes, estimating the relationship between outcomes and coding intensity. To develop prescription drug scores, we assigned therapeutic classes to beneficiaries based on their prescription drug utilization. We then regressed nondrug spending for TM beneficiaries in 2015 on demographic and therapeutic class identifiers for 2014 and used the coefficients to predict relative risk. PRINCIPAL FINDINGS: We found that, for each $1 increase in potential revenue resulting from coding intensity, MA plan bid submissions declined by $0.10 to $0.19, and another $0.21 to $0.45 went toward reducing plans' medical loss ratios, an indication of higher profitability. We found only a small impact on beneficiary's projected out-of-pocket costs in a plan, which serves as a measure of the generosity of plan benefits, and a $0.11 to $0.16 reduction in premiums. As expected, coding intensity's effect on bids was substantially larger in counties with higher levels of MA competition than in less competitive counties. CONCLUSIONS: While coding intensity increases taxpayers' costs of the MA program, enrollees and plans both benefit but with larger gains for plans. The adoption of policies to more completely adjust for coding intensity would likely affect both beneficiaries and plan profits.
Asunto(s)
Codificación Clínica/estadística & datos numéricos , Gastos en Salud/estadística & datos numéricos , Reembolso de Seguro de Salud/estadística & datos numéricos , Medicare Part C/organización & administración , Medicare Part D/organización & administración , Factores de Edad , Centers for Medicare and Medicaid Services, U.S./organización & administración , Grupos Diagnósticos Relacionados , Utilización de Medicamentos , Competencia Económica , Financiación Personal/estadística & datos numéricos , Estado de Salud , Humanos , Revisión de Utilización de Seguros , Medición de Riesgo , Factores Sexuales , Estados UnidosRESUMEN
OBJECTIVES: To compare relative readmission rates for beneficiaries enrolled in Medicare Advantage (MA) and traditional Medicare (TM) as suggestive evidence of changes in postdischarge care coordination and the quality of care delivered to Medicare beneficiaries. STUDY DESIGN: We used the Agency for Healthcare Research and Quality's 2009 and 2014 Healthcare Cost and Utilization Project State Inpatient Databases for 4 states with reliable sources of payment identifiers, linking these data to local area characteristics. Our outcome was the probability of a hospital readmission within 30 days of an index admission. We computed readmission rates overall and by subgroups, including for patients with multiple chronic conditions, by patients' state of residence, and by type of index admission. METHODS: We estimated linear probability models with hospital fixed effects including a wide array of patient-level characteristics relating to health status and sociodemographic characteristics. Standard errors were adjusted for clustering at the area level. RESULTS: Significantly lower all-cause readmission rates were found among MA enrollees relative to those in TM in both 2009 and 2014, suggesting an association between MA enrollment and higher quality of care. However, over the 2009-2014 period, MA enrollment was not associated with an increased reduction in readmission rates relative to TM. CONCLUSIONS: Although our focus was on a single measure of performance, the claims that managed care plans are spearheading changes in the delivery system are not supported by our finding that relative readmission rates were stable over the 2009-2014 period.
Asunto(s)
Medicare Part C , Readmisión del Paciente , Cuidados Posteriores , Anciano , Hospitalización , Humanos , Alta del Paciente , Estados UnidosRESUMEN
Spending on health care in the United States amounted to 17.9 percent of gross domestic product in 2017. Households paid for this care through out-of-pocket medical spending and a complex mix of out-of-pocket premiums, employer premium contributions, taxes, and subsidies that combined to finance private employer-sponsored insurance, nongroup insurance, and multiple public insurance programs. Our analysis examined the impact of this complex system of health care financing on households in the period 2005-16, tracking how economic and policy changes affected incidence-that is, the amount paid to finance health care, either directly or indirectly, by households as a share of their pretax income. Health care financing was regressive at the start of our study period, with households in the bottom 20 percent of income paying 26.8 percent of their income compared to about half that amount for those with income in the top 1 percent. By 2016 incidence had become approximately proportional (the same percentage across all income levels). In part, these results reflect increases in coverage through Medicaid and the Affordable Care Act Marketplaces, which are progressively financed through the federal tax system.
Asunto(s)
Financiación Personal/tendencias , Gastos en Salud/tendencias , Financiación de la Atención de la Salud , Patient Protection and Affordable Care Act , Factores Socioeconómicos , Estados UnidosRESUMEN
Obtaining health insurance coverage has historically been challenging for workers at small firms and the self-employed. Using data from the Medical Expenditure Panel Survey, we found that the overall uninsurance rate for these workers and their families declined by 5 percentage points over the past decade, but one-third of those with lower incomes remained uninsured in 2014-15.
Asunto(s)
Planes de Asistencia Médica para Empleados/estadística & datos numéricos , Cobertura del Seguro/estadística & datos numéricos , Seguro de Salud/estadística & datos numéricos , Medicaid/estadística & datos numéricos , Pacientes no Asegurados/estadística & datos numéricos , Gastos en Salud , Humanos , Cobertura del Seguro/tendencias , Seguro de Salud/tendencias , Encuestas y Cuestionarios , Estados UnidosRESUMEN
OBJECTIVE: To estimate the relative health risk of Medicare Advantage (MA) beneficiaries compared to those in Traditional Medicare (TM). DATA SOURCES/STUDY SETTING: Medicare claims and enrollment records for the sample of beneficiaries enrolled in Part D between 2008 and 2015. STUDY DESIGN: We assigned therapeutic classes to Medicare beneficiaries based on their prescription drug utilization. We then regressed nondrug health spending for TM beneficiaries in 2015 on demographic and therapeutic class identifiers for 2014 and used coefficients from this regression to predict relative risk of both MA and TM beneficiaries. PRINCIPAL FINDINGS: Based on prescription drug utilization data, beneficiaries enrolled in MA in 2015 had 6.9 percent lower health risk than beneficiaries in TM, but differences based on coded diagnoses suggested MA beneficiaries were 6.2 percent higher risk. The relative health risk based on drug usage of MA beneficiaries compared to those in TM increased by 3.4 p.p. from 2008 to 2015, while the relative risk using diagnoses increased 9.8 p.p. CONCLUSIONS: Our results add to a growing body of evidence suggesting MA receives favorable, or, at worst, neutral selection. If MA beneficiaries are no healthier and no sicker than similar beneficiaries in TM, then payments to MA plans exceed what is warranted based on their health status.
Asunto(s)
Revisión de la Utilización de Medicamentos/estadística & datos numéricos , Costos de la Atención en Salud , Medicare Part C/estadística & datos numéricos , Medicare/estadística & datos numéricos , Medicamentos bajo Prescripción/economía , Ajuste de Riesgo/economía , Gastos en Salud , Humanos , Medicare/economía , Medicare Part C/economía , Estados UnidosRESUMEN
Understanding the health care spending and utilization of various types of Medicaid enrollees is important for assessing the budgetary implications of both expansion and contraction in Medicaid enrollment. Despite the intense debate surrounding the Affordable Care Act (ACA), however, little information is available on the spending and utilization patterns of the nonelderly adult enrollees who became newly eligible for Medicaid under the ACA. Using data for 2012-14 from the Medical Expenditure Panel Survey, we compared health care spending and utilization of newly eligible Medicaid enrollees with those of nondisabled adults who were previously eligible and enrolled. We found that average monthly expenditures for newly eligible enrollees were $180-21 percent less than the $228 average for previously eligible enrollees. Utilization differences between these groups likely contributed to this differential.
Asunto(s)
Determinación de la Elegibilidad , Gastos en Salud/estadística & datos numéricos , Cobertura del Seguro/estadística & datos numéricos , Medicaid/estadística & datos numéricos , Adulto , Humanos , Patient Protection and Affordable Care Act/economía , Pobreza , Encuestas y Cuestionarios , Estados UnidosRESUMEN
OBJECTIVES: To compare how premiums and expected out-of-pocket medical costs (OOPC) vary with the length of time Medicare Advantage (MA) beneficiaries have been enrolled in their plans. STUDY DESIGN: Descriptive and fixed effects regression analyses. METHODS: Using linked administrative enrollment and plan data, we compared the costs of the MA plans that beneficiaries chose with the costs of other plans available to them. We show predicted values adjusted for age, gender, race/ethnicity, disability, individual health risk, presence of mental health diagnoses, health plan quality, relative size of the plan's provider network, and the number of years continuously enrolled in the same plan. To further address the possibility of bias, we included county-level fixed effects and compared results to a beneficiary-level fixed effects model. RESULTS: We found average spending on premiums and OOPC in enrolled plans exceeded such costs in the lowest-cost plan by $697 in 2013. Beneficiaries who remained in their plans for 6 or more years were most at risk of spending these higher amounts, paying $786 more than they would have spent in the lowest-cost plan compared with $552 for beneficiaries in their first year of enrollment. For each year a beneficiary remained in their same plan, their additional spending in excess of the minimum cost choice increased by roughly $50. CONCLUSIONS: MA beneficiaries could reduce their exposure to healthcare spending by switching to plans with lower premiums, although there may well be rational reasons for paying costs in excess of those of the lowest-cost plan.
Asunto(s)
Seguro/estadística & datos numéricos , Medicare Part C/economía , Anciano , Femenino , Humanos , Seguro/economía , Masculino , Factores de Tiempo , Estados UnidosRESUMEN
The Affordable Care Act (ACA) reformed the individual health insurance market. Because insurers can no longer vary their offers of coverage based on applicants' health status, the ACA established a risk adjustment program to equalize health-related cost differences across plans. The ACA also established a temporary reinsurance program to subsidize high-cost claims. To assess the impact of these programs, we compared revenues to claims costs for insurers in the individual market during the first two years of ACA implementation (2014 and 2015), before and after the inclusion of risk adjustment and reinsurance payments. Before these payments were included, for the 30 percent of insurers with the highest claims costs, claims (not including administrative expenses) exceeded premium revenues by $90-$397 per enrollee per month. The effect was reversed after these payments were included, with revenues exceeding claims costs by $0-$49 per month. The risk adjustment and reinsurance programs were relatively well targeted in the first two years. While there is ongoing discussion regarding the future of the ACA, our findings can shed light on how risk-sharing programs can address risk selection among insurers-a pervasive issue in all health insurance markets.
Asunto(s)
Aseguradoras/legislación & jurisprudencia , Patient Protection and Affordable Care Act/economía , Ajuste de Riesgo/estadística & datos numéricos , Prorrateo de Riesgo Financiero/legislación & jurisprudencia , Gastos en Salud , Humanos , Aseguradoras/economía , Seguro de Salud/economía , Patient Protection and Affordable Care Act/legislación & jurisprudencia , Método de Control de Pagos/legislación & jurisprudencia , Ajuste de Riesgo/economía , Prorrateo de Riesgo Financiero/economía , Estados UnidosRESUMEN
Eligibility for and enrollment in Medicaid can vary with economic recessions, recoveries, and changes in personal income. Understanding how Medicaid responds to such forces is important to budget analysts and policy makers tasked with forecasting Medicaid enrollment. We simulated eligibility for Medicaid for the period 2005-14 in two scenarios: assuming that each state's eligibility rules in 2009, the year before passage of the Affordable Care Act (ACA), were in place during the entire study period; and assuming that the ACA's expanded eligibility rules were in place during the entire period for all states. Then we correlated the results with unemployment rates as a measure of the economy. Each percentage-point increase in the unemployment rate was associated with an increase in the share of people eligible for Medicaid of 0.32 percentage point under the 2009 eligibility rules and 0.77 percentage point under the ACA rules. Our simulations showed that the ACA expansion increased Medicaid's responsiveness to changes in unemployment. For states that have not expanded Medicaid eligibility, our analysis demonstrates that increased responsiveness to periods of high unemployment is one benefit of expansion.
Asunto(s)
Recesión Económica , Determinación de la Elegibilidad/estadística & datos numéricos , Predicción , Medicaid/estadística & datos numéricos , Adulto , Humanos , Cobertura del Seguro/economía , Medicaid/tendencias , Persona de Mediana Edad , Patient Protection and Affordable Care Act , Encuestas y Cuestionarios , Desempleo/estadística & datos numéricos , Estados UnidosRESUMEN
Following the Affordable Care Act's insurance expansion provisions in 2014, the average health status and use of health care within coverage groups has likely changed. Medicaid enrollees and the uninsured were both healthier in 2014 than those respective groups were in 2013. By contrast, those with individual private insurance coverage appeared less healthy as a group.
Asunto(s)
Estado de Salud , Cobertura del Seguro/estadística & datos numéricos , Medicaid/economía , Pacientes no Asegurados/estadística & datos numéricos , Patient Protection and Affordable Care Act/economía , Adulto , Enfermedad Crónica/economía , Enfermedad Crónica/epidemiología , Estudios Transversales , Bases de Datos Factuales , Femenino , Accesibilidad a los Servicios de Salud , Disparidades en el Estado de Salud , Humanos , Cobertura del Seguro/economía , Masculino , Medicaid/estadística & datos numéricos , Persona de Mediana Edad , Evaluación de Necesidades , Patient Protection and Affordable Care Act/estadística & datos numéricos , Estados UnidosRESUMEN
Federal subsidies for health insurance premiums sold through the Marketplaces are tied to the cost of the benchmark plan, the second-lowest-cost silver plan. According to economic theory, the presence of more competitors should lead to lower premiums, implying smaller federal outlays for premium subsidies. The long-term impact of the Affordable Care Act on government spending will depend on the cost of these premium subsidies over time, with insurer participation and the level of competition likely to influence those costs. We studied insurer participation and premiums during the first two years of the Marketplaces. We found that the addition of a single insurer in a county was associated with a 1.2 percent lower premium for the average silver plan and a 3.5 percent lower premium for the benchmark plan in the federally run Marketplaces. We found that the effect of insurer entry was muted after two or three additional entrants. These findings suggest that increased insurer participation in the federally run Marketplaces reduces federal payments for premium subsidies.
Asunto(s)
Competencia Económica , Financiación Gubernamental , Seguro de Salud/economía , Patient Protection and Affordable Care Act , Estados UnidosRESUMEN
OBJECTIVES: To evaluate the sensitivity of Medicare beneficiaries to premiums and benefits when selecting healthcare plans after the introduction of Part D. STUDY DESIGN: We matched respondents in the 2008 Medicare Current Beneficiary Survey to the Medicare Advantage (MA) plans available to them using the Bid Pricing Tool and previously unavailable data on beneficiaries' plan choices. METHODS: We estimated a 2-stage nested logit model of Medicare plan choice decision making, including the decision to choose traditional fee-for-service (FFS) Medicare or an MA plan, and for those choosing MA, which specific plan they chose. RESULTS: Beneficiaries living in areas with higher average monthly rebates available from MA plans were more likely to choose MA rather than FFS. When choosing MA plans, beneficiaries are roughly 2 to 3 times more responsive to dollars spent to reduce cost sharing than reductions in their premium. We calculated an elasticity of plan choice with respect to the monthly MA premium of -0.20. Beneficiaries with lower incomes are more sensitive to plan premiums and cost sharing than higher-income beneficiaries. CONCLUSIONS: MA plans appear to have a limited incentive to aggressively price their products, and seem to compete primarily over reduced beneficiary cost sharing. Given the limitations of the current plan choice environment, policies designed to encourage the selection of lower-cost plans may require increasing premium differences between plans and providing the tools to enable beneficiaries to easily assess those differences.