The Spillover Effects of Nurse Practitioner Scope of Practice Expansions on Safety Net Program Participation: Evidence from WIC

Nurse practitioner (NP) scope of practice (SOP) reform has been shown to improve access to healthcare, leading to direct health benefits. However, given that NPs are likely to practice in underserved areas, liberalizing SOP may also have spillover benefits on safety net program participation, which would amplify the benefits of SOP expansion for underrepresented populations. In this paper, we study these potential spillovers by examining the effect of NP SOP expansions on enrollment in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Leveraging the staggered rollout of NP SOP expansions across states, we find that starting 4-5 years after SOP expansion, total WIC participation increases by 4% in treated states, which rises to 6.8% one decade after SOP expansion. This increase in total WIC enrollment is driven by increases in the enrollment of women and children. Mechanism analyses suggest that while access to healthcare is an important channel, the effect may also be driven by the fact that NPs are trained to deliver holistic, patient-centered care. Our results suggest that spillovers on safety net program participation are another pathway by which NP SOP expansions can improve the health and well-being of underserved populations.