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Characteristics of nurse practitioners and physician assistants in the United States

Hooker, Roderick S. PhD, MBA, PA (Adjunct Professor)1; Brock, Douglas M. PhD (Associate Professor)2; Cook, Michelle L. MPH, PhD(c) (Associate Vice President of Research)3

Author Information
Journal of the American Association of Nurse Practitioners: January 2016 - Volume 28 - Issue 1 - p 39-46
doi: 10.1002/2327-6924.12293
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The delivery of medical services in the United States requires a large corps of health professionals. Now into the new century, physician assistants (PAs) and nurse practitioners (NPs) have emerged as key players in the modern healthcare delivery system. Together their employment is substantial and their annual growth rivals that of allopathic and osteopathic physicians combined (Cooper, 2013). However, little information is available as to how they compare and if they are interchangeable.

Various opinions arise as to whether PAs and NPs provide similar or different roles in health delivery services (Chesluk & Homboe, 2010; Hing, Hooker, & Ashman, 2011; Margolius & Bodenheimer, 2010). Both provide services once the exclusive domain of physicians and are often employed in similar locations performing similar roles (Benitez, Coplan, Dehn, & Hooker, 2015; Hooker & Muchow, 2014). Useful examples include community health centers, prepaid managed care organizations, and the Veterans Affairs Medical Centers (Morgan, Everett, & Hing, 2014). What is less understood is whether there are meaningful differences between the two professions. A study examining the characteristics of NPs and PAs was undertaken. The objective was to explore the similarities and differences between the two health professions. Undertaking comparison research can improve service delivery if employers can substitute one for the other or incorporate both in team-based care. The research question was, “How do NPs and PAs overlap in distribution, roles, employment, wages, and other demographics?”


Data were obtained from a combination of public and proprietary sources to maximize the breadth of findings. Examination of separate sources also allowed for consistency checks of reported findings across sites. Specialty, practice, and employer information for NPs and PAs were drawn from association census surveys. Breakouts of employer type, wages, and wage projections were obtained through publicly available data sources. Employer type was based on Bureau of Labor Statistics (BLS) categories.

Data sources

Data were included from the following:

  1. BLS Occupational Employment and Statistics (OES, 1998–2013)
    • §BLS code: 29- 1071 PAs
    • §BLS code: 29–1171 NPs
  2. National Commission on the Certification of Physician Assistants (NCCPA, 2014)
  3. American Academy of Physician Assistants (AAPA, 2014)
  4. Physician Assistant Education Association (PAEA, 2014)
  5. American Association of Nurse Practitioners (AANP, 2014)
  6. American Association of Colleges of Nursing (AACN, 2014)
  7. Health Resources and Services Administration (HRSA, 2015)
  8. Nurse Practitioner Sample Survey (NPSS, 2014).

Data were obtained from the Occupational Employment Statistics (OES) program of the United States Department of Labor, BLS. The program collects hourly wages reports from employers and computes annualized wage based on hourly wage multiplied by 2080 h (40 h/week × 52 weeks). Through a business survey of approximately 1.2 million establishments and 3-year rolling sample periods, the OES program collects data to produce annual estimates. A statistically representative sample of employers provides estimates for worker employment and wages by occupation. Workers are classified in their Standard Occupational Classification (SOC) employment categories by job duties, not by licensing or job title. Therefore, a person with a PA or an NP license working as a hospital administrator would be counted as a hospital administrator in the OES data. The OES sample data are benchmarked to data from the Quarterly Census of Employment and Wages program.

OES statistics for each occupation code include means and percentile breakouts of 10%, 25%, 50%, 75%, and 90%. Estimates are based on all clinically employed NPs and PAs that are not employed outside of clinical activity such as administrators and academics.

Periodic surveys undertaken by the AAPA, AANP, AACN, and NCCPA provided gender, age, type of PA or NP practice specialty, and other demographic data for newly licensed and practicing PAs and NPs. These surveys were administered to association and nonassociation members having known contact information. The rate of return for the 2013–2014 AANP National NP Practice Site Census was 22% and 17% for the AAPA (AANP, 2015; AAPA, 2014). NCCPA return for 2014 was 80%. Annual faculty and director surveys conducted by the PAEA and the AACN provided training program data. The response rate for the 2013–2014 PAEA program survey was 100%. The response rate for the 2013 AACN survey of baccalaureate and graduate programs in nursing was 90%. Each survey, whether completed online or by mail, constituted a voluntary activity on the part of the respondent.


At year end of 2013, an estimated 201,000 NP/PAs were employed in American health delivery services in clinical practice (Table 1). Differences in state licensure and BLS employed findings were due to the way the data were captured; one licensed clinician may work in two or more locations and be counted as two employees. Females predominated (92.3% NPs and 75.0% PAs) with respective median ages of 49 and 38 years. Approximately 81.6% of PAs and 86.5% of NPs reported European/white race.

Table 1
Table 1:
Characteristics of PAs and NPs: 2013


Table 2 displays information about employment and employment settings. PAs reported, on average, 8.0 years of experience while NPs reported 10.4 years. Most NPs (86.5%) and all PAs were trained to practice in primary care fields (American definition of primary care, HRSA 2013). Half (51%) of the NP/PA cadre were employed in physician offices and one-fifth in general medical and surgical hospitals (including emergency medicine and acute care).

Table 2
Table 2:
Employment of PAs and NPs: 2013

According to the BLS, the three largest employers of PAs and NPs were “offices of physicians, general medical and surgical hospitals, and outpatient care centers.” These three settings represented 88.7% of PAs and 83.2% of NPs as reported by employers. No NPs were reported employed by the “federal executive branch,” the fourth largest employer of PAs (n = 2410, 2.7%) due to how the federal system defined the position and captured the data for BLS. “Home health services” were the fifth largest employer of NPs, accounting for 2.6% (n = 2940). Only 70 PAs, less than one-tenth of 1%, were reported working in home health services. More than one in 10 NPs or PAs reported two or more clinical positions (15.9% and 14.3%, respectively). Annual wages and projected employment growth through 2022 were similar for both professions.


The education of providers is presented in Table 3. NPs (97.6%) reported a higher percentage of either master's or doctoral degree in comparison to PAs (68.1%). At the end of 2014, the estimated number of graduates beginning careers was 15,000 NPs (2012–2013) and 7,556 PAs (2014). At least 98% of all PA graduates eventually obtained the national certificate required for state licensure. Nearly 97% of all NPs and 80% of all PAs report maintaining national certification.

Table 3
Table 3:
Education of PAs and NPs: 2013


The distribution of NPs and PAs in 51 U.S. jurisdictions (U.S. territories and Armed Forces were excluded) was factored in using a location quotient (Figure 1). The location quotient is a BLS value reflecting the ratio of the geographic area concentration of NPs or PAs to the national concentration of NPs or PA, based on census tracts and employment. This produces a complex relationship among region, population, and clinician distribution. Areas of NP concentration included the Mississippi-Ohio Valley, Northeast, and South (Figure 1a). Areas of PA concentration included the Northeast, Northern Plains, West coast, Texas, Oklahoma, Florida, and Wisconsin (Figure 1b).

Figure 1
Figure 1:
Distribution of NPs and PAs by location quotient.


The median wage of PAs and NPs was near parity across the first five practice specialties. “Outpatient care centers” had the highest median wage (PA = $46.88, NP = $45.00) and “colleges, universities, and professional schools” the lowest median wage (PA = $43.55, NP = $41.94). Further parsing of national wages revealed that the range for both PAs and NPs varied considerably within employment settings (Figure 2). The interquartile wage ranged from $15.91 for PAs employed in outpatient care centers to $10.98 for PAs employed in colleges, universities, and professional schools. The interquartile wage for NPs ranged from $12.89 for those employed in home healthcare services to $10.98 for those employed in colleges, universities, and professional schools.

Figure 2
Figure 2:
Wages: Four types of employers employing NPs and PAs.

Ratio of NPs to PAs by state

Figure 3 provides the ratio of employer-reported clinically practicing PAs to clinically practicing NPs. The majority of states have lower ratios of PAs to NPs than parity (ratio = 1.0). This results, in large part, from the greater number of practicing NPs (1.29 NPs for each PA). NPs were twice as numerous in Mississippi and Arkansas. Conversely, PAs were twice as numerous in Nevada. When an adjustment was made to compare relative versus absolute numbers of PAs to NPs—the estimate of the number of practicing PAs (1.29 × raw number)—the ranking remains the same but the ratios change. When described in relative terms, NPs were twice as numerous as PAs in six states (Mississippi, Arkansas, Alabama, Tennessee, Indiana, and Missouri). PAs were twice more likely to practice in Oklahoma and Nevada than NPs.

Figure 3
Figure 3:
Ratio of PAs to NPs by state (2013).


As of 2013, U.S. establishments reported employing approximately 201,000 licensed PAs and NPs in clinical roles. While these numbers may be somewhat inflated if dual reporting of employees was occurring, this still represented approximately 20% of the American health workforce holding an active state license to see patients as providers of care and prescribers of medication (e.g., allopathic and osteopathic physicians; HRSA, 2014). The per capita (100,000) numbers were 26.8 for PAs and 31.2 for NPs. Both had large numbers of educational programs in 2013/2014 (190 and 403, respectively) and, based on the historical PAEA and AANC reports, both were in significant growth phases of graduation rates. In 2014, the number of new PA graduates was estimated at 7,556; in 2013 the number of new NPs was at 15,000 (Fang, Li, Arietti, & Bednash, 2014; PAEA, 2014).

In many ways similarities between PAs and NPs are more pronounced than differences. Both were predominantly female (75.0% and 92.3%, respectively) and the vast majority was trained in primary care (100% and 88%, respectively). Approximately 32.1% of PAs and 81.6% of NPs were estimated to work as primary care providers using the HRSA definition. A majority of PAs (57.3%) and a plurality of NPs (45.6%) practiced in physicians' offices or in general medical and surgical hospitals (22.0% and 26.2%, respectively) as defined by the BLS.

The most common specialty areas for PAs included family medicine (20.5%), surgery (21.3%), emergency medicine (13.9%), and internal medicine specialties (7.7%). The most common specialty areas for NPs included family medicine (54.5%), adult health (19.3%), acute care (6.8%), women's health (4.9%), and mental health/psychiatry (3.7%). A bit of caution in these numbers is suggested because these were self-reported roles and some definitions may differ among associations.

PA median annual wage has exceeded inflation for over 15 years, suggesting demand has exceeded supply to date (Quella, Brock, & Hooker, 2015). As of 2013, estimates showed NP and PA hourly wages near parity, but PAs were more likely to be full-time (>31 h) and a higher percentage of NPs had advanced degrees. Both providers were in significant growth phases. The BLS-estimated replacement trends predicted PAs and NPs to grow, respectively, by 33,000 (35%) and 37,100 (31%) from 2012 to 2022 (BLS, 2014; HRSA, 2008).

Differences between the professions occurred for age, gender, distribution, and prevalence in specialty. The PA profession has become increasingly more female since the mid-1990s, with younger women replacing older men (Hooker & Muchow, 2014). Conversely, the age and gender distribution for NPs has remained more consistently female with little indication that significant change is occurring (AANP, 2015). The mean age difference between PAs and NPs (38 and 49 years, respectively) may result from nurses returning for an advanced degree as a later career choice rather than immediately after receiving their undergraduate degree. However, there is some evidence this age gap may be narrowing.

The distribution of PAs and NPs across specialties varied widely depending on how various categories were defined in surveys (Fraher, Morgan, & Johnson, 2015). The aggregate association survey data suggested that PAs are more often represented in procedural specialties such as surgery and emergency medicine. A minority of PAs could be classified as primary care providers. Conversely, NPs were more often represented in specialties such as women's health, pediatrics, geriatrics, and mental health (AANP, 2015; AAPA, 2014). A majority of NPs could be classified as primary care providers. PA and NP specialty differences were projected to shrink according to the Bureau of Health Professions with both better represented in pediatrics and women's health by 2020 (HRSA, 2008). As the role each play in these specialties is slowly emerging more granular questions arise. For example, do family medicine NPs and PAs emulate family medicine physicians in the range of diagnoses and services or is there only a partial overlap with NPs concentrated in women's health and diabetology, and PAs providing procedural services such as surgery and acute care? How these two professions play out in an expanded health insurance market under the Affordable Care Act of 2010 has many questions associated with it (Frogner, Spetz, Parente, & Oberlin 2015).


The greatest limitation of this research was the disparate data sources needed to create a composite of two large American health professions. Self-reported association census, survey, and membership data have been, historically, a sought-after source of information. However, self-reported data do not always interconnect with employer data or licensure data drawn from administrative sources within the utilizing organizations. Association surveys also increasingly suffer from diminishing rates of return, potential differential response rates across groups, and inadequate representation of small groups. Those not reporting may constitute significant biases in association data. Employer data, as collected from the BLS, also has its weakness as it has little means of adjustment to account for dual-employed clinicians (a statistic that may be as high as one sixth of all PA/NPs—unreported data from AAPA 2013 survey and AANP 2013–14 Census). Employment as a PA or an NP at two locations could confound the actual number. Licensure data in 2013 for PAs identified that 17% had two or more state licenses (Hooker & Muchow 2014). For NPs in 2014, an estimated 6% of active licenses in the nation were duplicates because NPs were licensed in more than one state (unpublished data from AANP). Whether both licenses were in effect was not assessed but one report identified conundrums in understanding the number and geographical distribution of primary care NPs in two states (Spetz, Fraher, Li, & Bates, 2015).


After a half-century of development, NPs and PAs have emerged as a large adaptive, and integral component of modern American health care. They are deployed in nearly all aspects of contemporary medicine, prescribe in almost every state, and produce a broad range of services. While PAs and NPs differ in some ways, they represent critical actors in emerging models for the delivery of primary and specialty health care. The increasing PA and NP integration into today's team-based system is accompanied by strong projections for their growth. In light of these findings and with improved modeling, predicted shortages of the medical workforce might need readjustment.


Each author, equally, made substantial contributions to the conception and design of the work, and the acquisition, analysis, and interpretation of data for the work. Each helped draft the work, revising it critically for important intellectual content, and had final approval of the version to be published. All authors agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.


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          Nurse practitioners; physician assistants; healthcare delivery; healthcare collaboration

          © 2016 American Association of Nurse Practitioners