Academic Appointments

Professional Education

  • Ph.D., MIT, Economics (2014)
  • B.A., Yale University, Economics & Mathematics (2008)


Stanford Advisees


All Publications

  • Subsidy Design in Privately Provided Social Insurance: Lessons from Medicare Part D. The journal of political economy Decarolis, F., Polyakova, M., Ryan, S. P. 2020; 128 (5): 1712–52


    The efficiency of publicly-subsidized, privately-provisioned social insurance programs depends on the interaction between strategic insurers and the subsidy mechanism. We study this interaction in the context of Medicare's prescription drug coverage program. We find that the observed mechanism is successful in keeping "raise-the-subsidy" incentives relatively low, acts much like a flat voucher, and obtains a level of welfare close to the optimal voucher. Across a range of counterfactuals, we find that more efficient subsidy mechanisms share three features: they retain the marginal elasticity of demand, limit the exercise of market power, and preserve the link between prices and marginal costs.

    View details for DOI 10.1086/705550

    View details for PubMedID 32431365

    View details for PubMedCentralID PMC7236560

  • Local Area Variation in Morbidity Among Low-Income, Older Adults in the United States: A Cross-sectional Study. Annals of internal medicine Polyakova, M., Hua, L. M. 2019


    Background: Recent studies have reported that low-income adults living in more affluent areas of the United States have longer life expectancies. Less is known about the relationship between the affluence of a geographic area and morbidity of the low-income population.Objective: To evaluate the association between the prevalence of chronic conditions among low-income, older adults and the economic affluence of a local area.Design: Cross-sectional association study.Setting: Medicare in 2015.Participants: 6363097 Medicare beneficiaries aged 66 to 100 years with a history of low-income support under Medicare Part D.Measurements: Adjusted prevalence of 48 chronic conditions was computed for 736 commuting zones (CZs). Factor analysis was used to assess spatial covariation of condition prevalence and to construct a composite condition prevalence index for each CZ. The association between morbidity and area affluence was measured by comparing the average of condition prevalence index across deciles of median CZ house values.Results: The mean age of study participants was 77.7 years (SD, 8.2); 67% were women, and 61% were white. The crude prevalence of 48 chronic conditions ranged from 72.5 per 100 for hypertension to 0.6 per 100 for posttraumatic stress disorder. The prevalence of these 48 chronic conditions was highly spatially correlated. Composite condition prevalence was on average substantially lower in more affluent CZs.Limitation: Low-income status measured on the basis of receipt of Medicare Part D low-income subsidies and not capturing persons not enrolled in Medicare Part D.Conclusion: Low-income, older adults living in more affluent areas of the country are healthier, and areas with poor health in the low-income, older adult population tend to have a high prevalence of most chronic conditions.Primary Funding Source: National Institute on Aging.

    View details for DOI 10.7326/M18-2800

    View details for PubMedID 31499522

  • Machine-Based Expert Recommendations And Insurance Choices Among Medicare Part D Enrollees HEALTH AFFAIRS Bundorf, M., Polyakova, M., Stults, C., Meehan, A., Klimke, R., Pun, T., Chan, A., Tai-Seale, M. 2019; 38 (3): 482–90
  • Private Provision of Social Insurance: Drug-Specific Price Elasticities and Cost Sharing in Medicare Part D AMERICAN ECONOMIC JOURNAL-ECONOMIC POLICY Einav, L., Finkelstein, A., Polyakova, M. 2018; 10 (3): 122–53
  • ACA Marketplace Premiums and Competition Among Hospitals and Physician Practices AMERICAN JOURNAL OF MANAGED CARE Polyakova, M., Bundorf, M., Kessler, D. P., Baker, L. C. 2018; 24 (2): 85-+


    To examine the association between annual premiums for health plans available in Federally Facilitated Marketplaces (FFMs) and the extent of competition and integration among physicians and hospitals, as well as the number of insurers.We used observational data from the Center for Consumer Information and Insurance Oversight on the annual premiums and other characteristics of plans, matched to measures of physician, hospital, and insurer market competitiveness and other characteristics of 411 rating areas in the 37 FFMs.We estimated multivariate models of the relationship between annual premiums and Herfindahl-Hirschman indices of hospitals and physician practices, controlling for the number of insurers, the extent of physician-hospital integration, and other plan and rating area characteristics.Premiums for Marketplace plans were higher in rating areas in which physician, hospital, and insurance markets were less competitive. An increase from the 10th to the 90th percentile of physician concentration and hospital concentration was associated with increases of $393 and $189, respectively, in annual premiums for the Silver plan with the second lowest cost. A similar increase in the number of insurers was associated with a $421 decrease in premiums. Physician-hospital integration was not significantly associated with premiums.Premiums for FFM plans were higher in markets with greater concentrations of hospitals and physicians but fewer insurers. Higher premiums make health insurance less affordable for people purchasing unsubsidized coverage and raise the cost of Marketplace premium tax credits to the government.

    View details for PubMedID 29461855

  • Private provision of social insurance: drug-specific price elasticities and cost sharing in Medicare Part D. American economic journal. Economic policy Einav, L., Finkelstein, A., Polyakova, M. 2018; 10 (3): 122–53


    We explore how private drug plans set cost-sharing in the context of Medicare Part D. While publicly-provided drug coverage typically involves uniform cost-sharing across drugs, we document substantial heterogeneity in the cost-sharing for different drugs within privately-provided plans. We also document that private plans systematically set higher consumer cost sharing for drugs or classes associated with more elastic demand; to do so we estimate price elasticities of demand across more than 150 drugs and across more than 100 therapeutic classes. We conclude by discussing the various channels that likely affect private plans' cost-sharing decisions.

    View details for PubMedID 30233766

    View details for PubMedCentralID PMC6141206

  • Marketplace Plans Provide Risk Protection, But Actuarial Values Overstate Realized Coverage For Most Enrollees HEALTH AFFAIRS Polyakova, M., Hua, L., Bundorf, M. 2017; 36 (12): 2078–84
  • Risk selection and heterogeneous preferences in health insurance markets with a public option JOURNAL OF HEALTH ECONOMICS Polyakova, M. 2016; 49: 153-168


    Conventional wisdom suggests that if private health insurance plans compete alongside a public option, they may endanger the latter's financial stability by cream-skimming good risks. This paper argues that two factors may contribute to the extent of cream-skimming: (i) degree of horizontal differentiation between public and private options when preferences are heterogeneous; (ii) whether contract design encourages choice of private insurance before information about risk is revealed. I explore the role of these factors empirically within the unique institutional setting of the German health insurance system. Using a fuzzy regression discontinuity design to disentangle adverse selection and moral hazard, I find no compelling support for extensive cream-skimming of public option by private insurers despite their ability to fully underwrite risk. A model of demand for private insurance supports the idea that heterogeneity in non-pecuniary preferences and long-term structure of private insurance contracts may be muting cream-skimming in this setting.

    View details for DOI 10.1016/j.jhealeco.2016.06.012

    View details for Web of Science ID 000384869400012

    View details for PubMedID 27454199

  • Regulation of Insurance with Adverse Selection and Switching Costs: Evidence from Medicare Part D AMERICAN ECONOMIC JOURNAL-APPLIED ECONOMICS Polyakova, M. 2016; 8 (3): 165-195

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