Does Public Health Insurance Expansion Influence Medical Liability Insurance Prices? The Case of the ACA’s Optional Medicaid Expansion

Medical liability insurance covers physicians’ liability, and its price could affect physicians’ practice. In this article, we use a unique county-level dataset to study how medical liability insurance prices of three specialties, internal medicine, general surgery, and obstetrics–gynecology (OB-GYN), changed after the Affordable Care Act (ACA) elective Medicaid expansion provision. The Medicaid expansion has largely increased the demand for health care services and potentially exposed physicians to higher medical liability risks. With higher expected losses, insurers could react by increasing medical malpractice insurance prices. We first study all counties in states that elected to expand Medicaid and compare them to counties in nonexpansion states. Then we narrow our analysis to consider differential effects in bordering counties with different Medicaid expansion statuses over the period 2010–2018. In both samples, we find significantly higher medical liability insurance prices 2 years after the expansion (on average) in expansion states in comparison to nonexpansion states, and the difference is larger for physicians practicing internal medicine (6–8% at 2 years after expansion) and general surgery (12–16% at 2 years after expansion) but less so for OB-GYN. Our OB-GYN results are likely because significant numbers of births were already covered under Medicaid and were not affected by the expansion. Our finding suggests that the expansion of health insurance increases liability costs to medical practitioners.