https://doi.org/10.1177/1077558716686889 Medical Care Research and Review 1–15 © The Author(s) 2017 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1077558716686889 journals.sagepub.com/home/mcr Empirical Research The Extraregulatory Effect of Nurse Practitioner Scope-of- Practice Laws on Physician Malpractice Rates Benjamin J. McMichael 1 , Barbara J. Safriet 2 , and Peter I. Buerhaus 3 Abstract Patients can hold physicians directly or vicariously liable for the malpractice of nurse practitioners under their supervision. Restrictive scope-of-practice laws governing nurse practitioners can ease patients’ legal burdens in establishing physician liability. We analyze the effect of restrictive scope-of-practice laws on the number of malpractice payments made on behalf of physicians between 1999 and 2012. Enacting less restrictive scope-of-practice laws decreases the number of payments made by physicians by as much as 31%, suggesting that restrictive scope-of-practice laws have a salient extraregulatory effect on physician malpractice rates. The effect of enacting less restrictive laws varies depending on the medical malpractice reforms that are in place, with the largest decrease in physician malpractice rates occurring in states that have enacted fewer malpractice reforms. Relaxing scope-of-practice laws could mitigate the adverse extraregulatory effect on physicians identified in this study and could also lead to improvements in access to care. Keywords malpractice, legal/regulatory issues, physicians, nurse practitioners, scope of practice This article, submitted to Medical Care Research and Review on September 19, 2016, was revised and accepted for publication on December 1, 2016. 1 Vanderbilt University, Nashville, TN, USA 2 Lewis & Clark Law School, Portland, OR, USA 3 Montana State University, Bozeman, MT, USA Corresponding Author: Benjamin J. McMichael, Owen Graduate School of Management, Vanderbilt University, 401 21st Avenue South, Nashville, TN 37203, USA. Email: benjamin.j.mcmichael@vanderbilt.edu 686889MCR XX X 10.1177/1077558716686889Medical Care Research and ReviewMcMichael et al. research-article 2017