Medicaid Coverage Expansions and Liability Insurance

Do changes in the population covered by health insurance affect liability insurers, who compensate billions of dollars in medical claims each year? We examine this question by exploiting the selective rollout across states of Medicaid expansions under the Affordable Care Act. Using data on insurer losses across a range of insurance lines, and employing a triple-difference research design that contrasts states, years, and lines of insurance, we demonstrate that coverage expansions reduce auto liability and workers' compensation outlays by 6–11 percent, but do not measurably impact other lines of insurance. Our analysis provides some of the first evidence regarding the use of the tort system particularized to the low-income population and is the first to consider the impacts of health insurance on medical professional liability and commercial auto insurance claims.