The Differential Effects of Malpractice Reform: Defensive Medicine in Obstetrics.

This article investigates how changes in medical malpractice pressure differentially affect patient groups through the practice of defensive medicine, using state-level tort reforms as exogenous variations in malpractice pressure. The authors develop and empirically test a theoretical model predicting that reduced malpractice pressure decreases health care spending among patients with good access to care ("full-access") but increases spending among those with poor access ("limited-access"). Using a large U.S. birth dataset from 1989 to 2001, they proxy access by the timeliness of prenatal care initiation and health care spending by cesarean section (C-section) rates. The findings show that tort reforms reducing malpractice pressure lower C-section rates by 4.75% among full-access mothers but increase rates by 7.59% among limited-access mothers, consistent with defensive medicine rather than offensive medicine explanations. Additional analyses suggest that reduced malpractice pressure modestly improves access and reduces adverse birth outcomes, particularly respiratory distress requiring assisted ventilation, among vulnerable populations. These results highlight the complexity of malpractice reform effects, emphasizing that defensive medicine leads to heterogeneous impacts across patient groups and that policy evaluations should consider access differences to better predict outcomes.