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Original Research

Primary care workforce paradox

A physician shortage and a PA and NP surplus

White, Ryan MS, MPH, PA-C; Keahey, David PA-C, MSPH; Luck, Morgan MS, PA-C; Dehn, Richard W. MPA, PA-C, DFAAPA

Author Information
Journal of the American Academy of Physician Assistants: October 2021 - Volume 34 - Issue 10 - p 39-42
doi: 10.1097/01.JAA.0000791476.25727.d9
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Primary care physician shortages are widely reported in the literature.1,2 The Association of American Medical Colleges (AAMC) projects a shortage of 21,100 to 55,200 primary care physicians by 2033; the US Health Resources and Services Administration (HRSA) predicts a shortage of more than 23,000 primary care physicians by 2025.1,2 Physician assistants (PAs) and NPs, who provide a similar spectrum of services as primary care physicians, have been cited as a moderating factor on projected primary care physician shortages.1,3-6

The calculation of PA and NP contributions toward alleviating future healthcare provider shortages depends on the degree to which these providers approximate the clinical productivity of primary care physicians. The AAMC estimates its physician projections using moderate use and high use PA and NP approximation scenarios, with the moderate scenario using a PA- or NP-to-physician productivity ratio of 0.25 (suggesting that four PAs or NPs would replace the efforts of one physician).1 The high-use scenario establishes a 0.5 productivity ratio.1 In other words, the AAMC predicts that PAs and NPs provide no more than 25% to 50% of the clinical productivity of physicians in primary care settings.

These ratios have been called into question, indicating that primary care PA and NP productivity may be significantly undervalued in the AAMC and other models.7 Previous studies have found that PA productivity in primary care practices is similar to that of physicians.8,9 Simulation models suggest that even a 0.2 productivity ratio, paired with pooled physician teams, can eliminate projected physician shortages.10 HRSA has stated that “[M]ore effective incorporation of NP and PA services in care delivery could mitigate regional disparities and improve access to primary care services.”2

Paradoxically, HRSA and others predict an oversupply of primary care PAs and NPs.2,11 Simultaneous predictions of primary care physician shortages and an oversupply of PAs and NPs suggests the need for further investigation into the assumptions on which these projections are based. Accurate estimates of primary care PA and NP productivity are critical in providing context to decision-makers as they consider primary care workforce policy approaches.

Federally qualified health centers (FQHCs) are a critical component of the primary care delivery system, providing care to a wide variety of patients regardless of health insurance status or ability to pay. These practices increasingly rely on the PA and NP workforce, with a 1.02 PA- or NP-to-physician employment ratio reported in 2019, creating an ideal setting in which to study provider productivity.12 In this study, we examine FQHC visits per FTE to compare the productivity of physicians, PAs, and NPs.


FQHCs report annual performance measures through the Uniform Data System (UDS), which documented 81,181,215 medical encounters in 2019.13 An encounter or visit occurs in FQHC facilities and outreach locations as well as in hospitals and nursing or extended care facilities. Encounters may also include telemedicine.14

Among the measures reported are the number of clinic visits and full-time equivalents (FTEs) by provider type.15 Physician specialties reported are family physicians (FPs), general practitioners, internists, obstetrician/gynecologists, pediatricians, and a category inclusive of “other specialty physicians.” NP, PA, and certified nurse-midwife (CNM) data are individually reported.

To estimate PA- or NP-to-family-physician clinical productivity ratios, the number of clinic visits per FTE for PAs and NPs was divided by clinic visits per FTE for family physicians, which produced a PA-to-FP ratio and an NP-to-FP ratio for each year. CNMs, obstetricians/gynecologists, and other specialty physicians were excluded from the analysis due to their narrower scope of practice and limited generalizability to primary care.

Productivity ratios were recalculated using the clinic visits per FTE for all primary care physicians as the denominator (excluding obstetrician/gynecologists and other specialty physicians), to capture the average productivity of general practitioners, internists, and pediatricians.


Clinic visits per FTE and productivity ratios are displayed in Figure 1 and clinic visits and FTEs by provider type are provided in Table 1. Clinic visits and FTE increased for all provider types between 2016 and 2019, but visits per FTE decreased for all provider types during this time period. The growth in FTE outpaced the growth in clinic visits for all provider types.

PA- and NP-to-physician productivity ratios in FQHCs, 2016-2019Productivity ratios were calculated by dividing PA or NP visits per FTE by physician visits per FTE and FP visits per FTE. The physician category includes FPs, general practitioners, internists, and pediatricians, and excludes obstetrician/gynecologists and other specialty physicians.
TABLE 1. - Provider clinical productivity in FQHCs, 2016-2019
The physician category includes FPs, general practitioners, internists, and pediatricians, and excludes obstetrician/gynecologists and other specialty physicians.
FTE Clinic visits Visits per FTE Provider to FP ratio Provider to total physicians ratio
2019 FPs 6,441.49 18,233,695 2,830.66
Total physicians 12,120.82 35,412,947 2,921.66
PAs 3,348.28 9,420,638 2,813.58 0.99 0.96
NPs 10,512.54 26,364,33 2,507.89 0.89 0.86
Combined PA/NP 13,860.52 35,784,974 2,581.79 0.91 0.88
2018 FPs 6,117.26 17,742,535 2,900.41
Total physicians 11,574.79 34,191,477 2,953.96
PAs 3,227.05 9,006,061 2,790.8 0.96 0.94
NPs 9,657.64 24,183,141 2,504.04 0.86 0.84
Combined PA/NP 12,884.69 33,189,202 2,575.86 0.89 0.86
2017 FPs 5,933.44 17,549,536 2,957.73
Total physicians 11,172.71 33,741,457 3,019.99
PAs 3,076.92 8,677,475 2,820.18 0.95 0.93
NPs 8,851.71 22,365,601 2,526.7 0.85 0.84
Combined PA/NP 11,928.63 31,043,076 2,602.4 0.88 0.86
2016 FPs 5,721.43 17,618,401 3,079.37
Total physicians 10,749.46 33,439,834 3,110.84
PAs 2,924.92 8,322,036 2,845.22 0.92 0.91
NPs 7,878.98 20,170,946 2,560.1 0.83 0.82
Combined PA/NP 10,803.9 28,492,982 2,637.29 0.86 0.85

The combined per-FTE clinical productivity of PAs and NPs was similar to that of all physicians, increasing from 0.85 in 2016 to 0.88 in 2019. The PA productivity ratios were greater than the NP productivity ratios. The PA-to-all physician productivity ratio was 0.96 (0.86 for NPs) in 2019, and the PA-to-FP productivity ratio was calculated at 0.99 in 2019 (0.89 for NPs).


The aging US population, geographic maldistribution of clinicians, and overall US population growth amplify concerns about projected primary care physician shortages. Projected shortages have led to a number of federal, state, and institutional policy initiatives to increase the primary care workforce. These include HRSA's National Health Service Corps scholarship and loan repayment programs, which encourage providers to work in health professional shortage areas; the Primary Care Training and Enhancement program supporting clinical learning in these settings; and expanded funding for primary care physician residency programs.16 Concurrently, US medical school enrollment has increased more than 30% over the past 2 decades.17

The PA and NP professions have also experienced significant labor market growth in recent years.18 Because of the contributions of PAs and NPs in primary care, it is counterintuitive to imagine a future with significant primary care physician shortages and at the same time surpluses of PAs and NPs. The proportion of FQHC encounters with PAs and NPs relative to physicians continues to increase each year and is similar to physician encounter productivity.

These data suggest that primary care workforce projections that employ non-evidence based substitution ratios, including the 0.25 and 0.5 ratios used by the AAMC, substantially underestimate the productivity contributions of PAs and NPs and leads to significant inflation of primary care physician shortage projections. FQHCs now employ more PA and NP FTEs than physician FTEs, indicating an increased reliance on the PA and NP workforce. If PAs and NPs were 25% to 50% as productive as physicians, it is implausible that FQHCs would employ PAs and NPs at a greater rate than physicians. The costs of recruiting, hiring, onboarding, and employing two to four PAs or NPs to achieve the productivity of one physician call these low ratios into question. In the context of physician teams, if a productivity ratio as low as 0.2 can eliminate projected physician shortages as suggested by Green and colleagues, these shortages would be unlikely to persist at productivity ratios above 0.5.10


Encounter-level UDS data were not available to perform case mix adjustment. The productivity ratios, therefore, do not reflect patient complexity. A study by Morgan and colleagues demonstrated the importance of case mix adjustment when comparing outcomes across provider types.19 This study, however, was not specific to primary care encounters.19 Recent studies find that patient characteristics are similar across provider types in FQHCs. Kurtzman and Barnow examined nationally representative FQHC data from the National Ambulatory Medical Care Survey-Community Health Center component and found no significant differences in the number of chronic conditions, number of medications, visit type, and number of annual visits between patients treated by physicians, PAs, and NPs.20 Previous analyses of national datasets have yielded similar results, with minimal differences in patient diagnoses, diagnostic testing, and medications prescribed by provider type.21 Other studies found minimal differences in patient characteristics across provider type, with a near-equivalent proportion of patients who consider physicians and PAs to be their primary care provider.3,4

Second, the publicly available UDS reports do not include encounter-level data, meaning that the extent of provider team involvement in each clinic visit could not be determined. A percentage of the visits to a PA or NP may have involved consultation with a physician. Conversely, a percentage of the physician visits also may have included consultation with a PA or NP team member. Third, the FQHC patient population and provider use may not be generalizable to other primary care practices where the patients served likely face fewer social needs and barriers to care. Given FQHC staffing needs, however, PAs and NPs in this setting may practice with greater autonomy and closer to their full scope of practice as permitted by state law than PAs and NPs in private practices.


Our findings from a national study of FQHCs suggest that organizations and researchers who make workforce projections should carefully reexamine productivity models and substitution ratios for primary care clinicians. This analysis suggests that projections that employ a 0.25 or 0.5 substitution ratio of PAs- or NPs-to-physicians underestimate the productivity and thus the contributions of PAs and NPs that result in an overestimation of existing and future primary care physician shortages. New analyses should consider evidence-based PA and NP productivity measures or explore measures of team- or practice-level productivity. Our analysis has important implications for primary care workforce policies and is echoed in the HRSA statement that “[W]ith delivery system changes and full utilization of NP and PA services, the projected shortage of 23,640 [primary care physician] FTEs can be effectively mitigated.”2


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    primary care; workforce; productivity; federally qualified health centers; physician assistant; NP

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