Nurse Scope of Practice Expansions and Physician Location

More than half of US states have expanded nurse scope of practice (SOP), allowing advanced practice registered nurses (APRNs) to provide primary care without physician supervision. Physician groups have lobbied against SOP laws, but harm to physicians depends on whether ARPNs are substitutes or complements to primary care physicians (PCPs). If they are substitutes, expanded SOP can harm PCPs by introducing competition. If they are complements, expanded SOP can benefit PCPs through division of patient load. This study seeks to disentangle these two pathways by examining PCP location response to SOP expansion using a difference-in-differences design, leveraging staggered state adoption of SOP laws. I find that neither aggregate PCP location nor new PCP location responds to expanded SOP. However, PCPs and new PCPs increase in counties with high pre-period APRN presence, suggesting that APRNs and PCPs are complements in these markets. Overall, I find little evidence that SOP expansion induces physicians to leave markets due to ARPN competition. Instead, expanded SOP appears to allow APRNs to provide primary care without crowding out incumbent PCPs.