Academic Appointments

Professional Education

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


2019-20 Courses

Stanford Advisees

  • Med Scholar Project Advisor
    Johan Hong
  • Doctoral Dissertation Reader (AC)
    Yiqun Chen
  • Doctoral (Program)
    Yiqun Chen, Jack Ching, KYU LEE, Tess Ryckman


All Publications

  • 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
  • Machine-Based Expert Recommendations And Insurance Choices Among Medicare Part D Enrollees. Health affairs (Project Hope) Bundorf, M. K., Polyakova, M., Stults, C., Meehan, A., Klimke, R., Pun, T., Chan, A. S., Tai-Seale, M. 2019; 38 (3): 482?90


    Choosing a health insurance plan is difficult for many people, and patient-centered decision support may help consumers make these choices. We tested whether providing a patient-centered decision-support tool-with or without machine-based, personalized expert recommendations-influenced decision outcomes for Medicare Part D enrollees. We found that providing an online patient-centered decision-support tool increased older adults' satisfaction with the process of choosing a prescription drug plan and the amount of time they spent choosing a plan. Providing personalized expert recommendations as well increased rates of plan switching. Many people who could have accessed the tool chose not to, and the characteristics of people who used the tool differed from those who did not. We conclude that a patient-centered decision-support tool providing personalized expert recommendations can help people choose a plan, but different approaches may be necessary to encourage more people to periodically reevaluate their options.

    View details for PubMedID 30830808

  • 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
  • Marketplace Plans Provide Risk Protection, But Actuarial Values Overstate Realized Coverage For Most Enrollees. Health affairs (Project Hope) Polyakova, M., Hua, L. M., Bundorf, M. K. 2017; 36 (12): 2078?84


    The Affordable Care Act (ACA) has increased the number of Americans with health insurance. Yet many policy makers and consumers have questioned the value of Marketplace plan coverage because of the generally high levels of cost sharing. We simulated out-of-pocket spending for bronze, silver, or gold Marketplace plans (those having actuarial values of 60 percent, 70 percent, and 80 percent, respectively). We found that for the vast majority of consumers, the proportion of covered spending paid by the plans is likely to be far less than their actuarial values, the metric commonly used to convey plan generosity. Indeed, only when annual health care spending exceeds $16,500 for bronze plans, $19,500 for silver plans, and $21,500 for gold plans do plans in these metal tiers cover the proportion of costs matching their actuarial values. While Marketplace plans substantially reduce consumers' exposure to financial risk relative to being uninsured, the use of actuarial values to communicate plan generosity is likely to be misleading to consumers.

    View details for PubMedID 29200356

  • 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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