The Extraregulatory Effect of Nurse Practitioner Scope-of-Practice Laws on Physician Malpractice Rates.

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.