Impacts of Medicaid Expansion on the Liability Insurance Industry

Abstract

This dissertation studies the impact of Medicaid expansion on the liability insurance industry. Within the three chapters, the first two chapters focus on the medical liability insurance industry, and the third chapter focuses on the auto insurance industry. Chapter 1, “Medicaid Expansion and Medical Liability Costs”, examines the impact of health insurance expansion on medical liability costs using the case of the Affordable Care Act’s (ACA) Medicaid expansion. Medicaid expansion has increased the demand for medical services, but in doing so it may also have increased physicians’ liability in medical practice. By studying malpractice costs to insurers, medical practitioners, and hospitals in the U.S. for the period 2010–2018, we find insurers operating in states with Medicaid expansion experienced significantly higher medical liability costs than those in non-expansion states. While insurers in expansion states did increase premiums, the increase was not enough to fully offset rising costs. Moreover, we find that tort reforms did not mitigate ACA-induced malpractice liability costs. We show this is because Medicaid expansion increased malpractice costs mainly by increasing claim frequency while tort reforms generally focus on reducing claim severity. We further find little evidence that hospitals paid higher malpractice insurance premiums, self-insurance, or incurred higher out-of-pocket medical liability losses after Medicaid expansion. Taken together, our results imply that it is medical practitioners and malpractice insurers who bear the rising medical liability costs. Chapter 2, “Medicaid Expansion and Medical Liability Insurance Prices” extends the first chapter to study the impact of Medicaid expansion on medical liability insurance prices for three specialties, internal medicine, general surgery, and obstetrics-gynecology (OB-GYN). As Medicaid expansion increased medical liability costs to insurers, they may react by increasing medical malpractice insurance prices. By studying counties in expansion states and non-expansion states and bordering counties with different Medicaid expansion status over the years from 2010-2018, we find that Medicaid expansion leads to significantly higher medical liability insurance prices two years after the expansion on average and the impact is strongest for internal medicine and general medicine but less so for OB-GYN. Our finding suggests that the expansion of health insurance could increase liability costs to medical practitioners. Auto insurance provides coverage of healthcare for injured drivers even for those without traditional health insurance coverage. The expansion of public health insurance provides low-income injured drivers with an additional source of coverage for medical bills. This may change drivers’ incentives for using auto insurance and the ultimate payments made by auto insurers. In Chapter 3, “Public Health Insurance Expansion and Auto Insurance: The Case of Medicaid Expansion”, we first use a simple theoretical model to illustrate how obtaining public health insurance mitigates the incentive of insured drivers to engage in claims buildup. We then empirically test how the Affordable Care Act (ACA)’s Medicaid expansion changed the medical costs covered by auto insurance. By studying private passenger auto insurers in expansion states and non-expansion states between 2010 and 2018, we find that Medicaid expansion led to significantly lower auto insurance losses and premiums. We further show that the results were driven by the decreasing losses and premiums for third-party liability insurers but not in the states with no-fault insurance.