ABSTRACT
Objective: Understanding the geographic distribution of physician assistants (PAs) can inform health care workforce planning. This study examines PA supply by state and county. Also examined is the relationship between PA supply and level of urbanization as well as state laws governing PA practice.
Methods: The addresses of all NCCPA-certified PAs were identified from the AAPA Masterfile and used to estimate PA to population ratios. PA supply in rural and urban communities was analyzed by linking records from the AAPA Masterfile to the 2007 Federal Area Resource File using county identifiers. PA supply was also examined according to the favorability of state laws towards PA practice.
Results: State PA supply varies from 0.6 PAs per 10,000 population in Mississippi to 5.6 PAs per 10,000 population in Alaska. Counties with PAs were more likely to be urbanized, whereas those without PAs were more likely to be rural. States identified as “unfavorable” for PA practice were found to have notably lower PA supply compared to other states.
Conclusions: Substantial variation exists in the PA-to-population ratio among states, which may be related in part to state practice laws. At a more local level, counties without PAs are more likely to be rural than counties with PAs. The distribution of PAs is likely to remain geographically uneven in the absence of signifi cant policy efforts to attract PAs to practice in rural communities.
Physician assistants (PAs) are licensed by the state to practice medicine with physician supervision, and the limits of PA ability to practice are determined largely at the state level. Because of the important role states play in developing a health care workforce to meet the needs of their populations, it is important to know each state's current supply of PAs, whether variations exist among states, and what factors may be related to a state's PA supply. The analyses described in this report were intended to offer insight into the current supply and distribution of PAs; this data will assist the profession in identifying areas of the country that could most benefit from the anticipated growth in PAs. Additionally, analyses are presented to examine the relationship between PA supply and factors believed to drive PA location of practice, including the extent to which the locations where PAs practice are urbanized and the types of state laws governing PA practice.
METHODS
Data from the American Academy of Physician Assistants (AAPA) December 2009 Masterfile were used to estimate PA supply at the state and county level. The AAPA Masterfile contains records on all people in the United States who are eligible to practice as a PA. Data maintained in this file are gathered from enrollment and graduation rosters that are forwarded to AAPA from PA programs, individuals seeking to obtain AAPA membership, the National Commission on Certification of Physician Assistants (NCCPA), state licensing agencies, and the US Postal Service. Information is updated when AAPA membership is renewed, when addresses change, and on a quarterly basis as AAPA acquires updated certification and licensing data. The addresses of all NCCPA-certified PAs were identified from the Masterfile; these addresses were used to assign PAs to a state and county for purposes of estimating the PA-to-population ratios for all states. Only certified PAs were used in this study because they are likely to be clinically practicing.
Analyses of PA supply in rural and urban communities were made possible by linking records from the AAPA Masterfile to the 2007 Area Resource File (ARF), using county identifiers.* Maintained by the Health Resources and Services Administration, the ARF is a county-level database of information on health care professions, hospitals and health facilities, and population characteristics. The ARF contains data necessary to categorize counties by level of urbanization. The Rural-Urban Continuum Codes, established by the United States Department of Agriculture's Economic Research Service, classify counties on the basis of population size, degree of urbanization, and adjacency to metro areas.
* Masterfile records contain information on PA home and work zip codes. Although ARF data are only available
at the county level, SASHELP.ZIPCODE was used to identify the county corresponding to the zip codes
in the Masterfile. Zip code of residence was used to assign respondents to a county in those cases for which
employer zip codes were not available.
RESULTS
Supply of physician assistants in the United States by state As shown in Figure 1, the supply of PAs varied substantially across the country. The number of PAs per 10,000 population ratio ranged from a low of 0.6 in Mississippi to a high of 5.6 in Alaska, more than a nine-fold difference (Table 1). Aside from Alaska, states with the greatest supply of PAs included South Dakota (4.9 PAs/10,000), Maine (4.1 PAs/10,000), West Virginia (4.1 PAs/10,000), Nebraska (4.0 PAs/10,000) and Connecticut (4.0 PAs/10,000). With the exception of California, New Jersey, and Hawaii, states with the lowest PA supply were concentrated in Southern and mid-central states. Mississippi, Arkansas, Missouri, Indiana, and Alabama, for instance, each had a PA supply of 1.2/10,000 population or less.
Supply of PAs by county PA supply was also examined at the county level, and counties with no PAs were identified (Figure 2). Across the country, 38 of the 50 states have at least one county without a PA. About 20% of US counties, a total of 627, were found to have no one eligible to practice as a PA. Of note, in Mississippi, 74% of counties (71 of 82 counties) had no PAs, suggesting that 46% of the state population may have limited access to these providers (Table 2). Sixty (60) percent of Arkansas counties (45 of 75 counties) have no PAs, and approximately 28% of the state population resides in these 45 counties. In Missouri, 61 of 82 counties have no PAs.