Bio

Academic Appointments


Professional Education


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

Teaching

2018-19 Courses


Stanford Advisees


Publications

All Publications


  • 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-+

    Abstract

    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 Web of Science ID 000425326700008

    View details for PubMedID 29461855

  • 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

    Abstract

    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