Article Text

Original research
Cross-sectional analysis of US scope of practice laws and employed physician assistants
  1. Virginia L Valentin1,
  2. Shahpar Najmabadi1,
  3. C Everett2
  1. 1Department of Family and Preventive Medicine, University of Utah, Salt Lake City, Utah, USA
  2. 2Community and Family Medicine, Duke University, Durham, North Carolina, USA
  1. Correspondence to Dr Shahpar Najmabadi; s.najmabadi{at}


Objective This study examined if the variation in physician assistant (PA) state scope of practice (SOP) laws across states are associated with number of employed PAs, PA demographics and PA/population ratio per state. The hypothesis was that less restrictive SOP laws will increase the demand for PAs and the number of PAs in a state.

Design Retrospective cross-sectional analysis at three time points: 1998, 2008, 2017.

Setting Fifty states and the District of Columbia.

Participants Employed PAs in 1998, 2008, 2017.

Methods SOP laws were categorised as permissive, average and restrictive. Three national datasets were combined to allow for descriptive analysis of employed PAs by year and SOP categories. We used linear predictive models to generate and compare PA/population ratio least square means by SOP categories for each year. Models were adjusted for percent female PA and PAs mean age.

Results There was a median PA/population ratio of 23 per 100 000 population in 1998 and 33 in 2017. A heterogeneous expansion of SOP laws was seen with 17 states defined as super expanders while 15 were never adopters. In 2017, comparing restrictive to permissive states showed that in adjusted models permissive SOP laws were associated with 11.7 (p .03) increase in ratio of employed PAs per 100 000 population, demonstrating that states with permissive SOP laws have an increased PA density.

Conclusions There has been steady growth in the mean PA/population ratio since the turn of the century. At the same time, PA SOP laws in the USA have expanded, with just 10 states remaining in the restrictive category. Permissive SOP laws are associated with an increase in the ratio of employed PAs per state population. As states work to meet the projected physician need, SOP expansion may be an important policy consideration to increase the PA workforce.

  • health policy
  • organisation of health services
  • organisational development

Data availability statement

BLS has a public use linkage to access Labor Statistics data 1998–2017. The data from AAPA on PA census and legislative history was requested through AAPA research department.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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Data availability statement

BLS has a public use linkage to access Labor Statistics data 1998–2017. The data from AAPA on PA census and legislative history was requested through AAPA research department.

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  • Collaborators None.

  • Contributors VLV, SN and CE were involved in the data analysis, interpretation, drafting the manuscript and reviewed/edited the manuscript.

  • Funding This project was funded by a grant award from the Physician Assistant Education Association, Washington, DC and the American Academy of Physician Assistants, Alexandria, VA. Grant number: N/A.

  • Disclaimer Funding of this project does not necessarily constitute an endorsement of the findings of this research report by either organisation.

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  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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