The predictive model suggests that the overall supply of PAs is likely to increase by 72% to 127,821 PAs by 2025. With one-third of PA programs inaugurated since 2000, and two-thirds inaugurated since 1991, growth is likely to continue, although not at the same trajectory.
The decline in the percentage of PAs identifying primary care in the AAPA census has shown a slow and steady downward trend of 1%–2% per year since the turn of the century, and a plateau was not predictable in our model. This subject is murky for a number of reasons. PA census respondents separately identified occupational medicine, geriatric medicine, corrections medicine, hospital medicine, public health, and women's health; such roles are primary care in nature but did not meet our definition. At the same time, military PAs use a wide range of skills and roles beyond primary care; however, without their own category, they often select family medicine or general internal medicine on the census form. Finally, while the percentage of primary care PAs may be declining in census statistics, the annual cadre of PAs producing primary care is growing, and a statistical counterbalance may be in effect.
Annual attrition estimates were projected at 4%, 5%, and 6% for the model to provide a range of those departing clinical activity. These attrition assumptions are bolstered by BLS observations for various professionals such as doctors and lawyers at various times in their careers and are offset by a rising percentage of seniors working past 65 years of age.19
If the mean age of a PA at graduation is 29 years, then an average 35-year career as a PA seemed reasonable to our advisors. The PA profession is a relatively young one in age composition (with the mean age at graduation likely to remain around 30 years for the next decade), thus providing an annual production that exceeds attrition. The first two decades of the profession comprised older males with at least one career behind them. Currently, a larger cadre of younger females with no prior career is replacing a smaller, older generation. Furthermore, the age distribution curve of PAs in the 2009 census is more skewed to the right than a bell shape. Finally, our conservative attrition rate of 5% is tempered by the observation that the average age of all PAs who reported being retired is 63 years, which is considered relatively young.15
Retention is the obverse side of attrition, and 82% of people who graduated from a PA program were estimated to be clinically active in 2009.15
Accurate attrition and retention rates for PAs are challenging to estimate as no experiential data are available and because individuals may leave the workforce for a few years and then return, a pattern that is not easily captured. Turning to other studies, a plurality (42%) of PA faculty was uncertain about retiring prior to age 62 years if given the option.20
The annual attrition of PAs in the Veterans Administration (the largest employer of PAs) is 9%, with some PAs departing the Veterans Health Administration with a federal pension but reentering in the private sector.21
We obtained a similar attrition rate of 9% from the Department of Defense, indicating PAs completing 20- to 30-year careers (Personal communication, William Tozier, U.S. Army, March 2010). These high attrition and retirement rates are mentioned as the only reliable data at the time of this study and do not reflect the general population. Death and disability are also absent from PA statistics.
Some variables that influence supply and have predictable values were incorporated into this model. Specifically, we included the average number of graduates per program; 3% who never obtained certification; an aging, predominantly male cadre; and the median age of graduates who are young and female. Growth factors included an increase in the number of universities developing PA programs and class expansion in some older programs. We think these are reasonable assumptions, as graduate programs such as PA education are financially advantageous for institutions, and most of the new programs in the pipeline are private institutions. Furthermore, PA programs are sponsored by less than 5% of U.S. institutions of higher education and less than 50% of academic health centers, suggesting that there is room for new program installation. Constraints on PA program expansion include faculty shortages and an inadequate number of clinical training sites, as PA programs compete with allopathic and osteopathic medical schools and NP programs for student placement.15,16
Another factor is debt obligation, which appears to have a dampening effect on enrollment, at least in proprietary institutions. The opportunity cost of a PA education in a private university exceeds $100,000 and is likely to grow, which could stifle applicant trends.2
The effect of age and gender on the U.S. labor force is still playing out and could not be estimated with the current data. Based on applicants entering PA education, the mean age of graduates has leveled off at 30 years, and the female PA composition will plateau at 66%. Observations in developed countries suggest that a gender shift is not unique to the U.S., and women are beginning to dominate in a number of historically male domains.22
Women entering the PA profession are younger and more likely to take time off for family development.23
Retention in the PA workforce is expected to remain at the current level for a number of reasons. PA career satisfaction is generally considered high, and a national poll found that most practicing PAs would select this career again.24
PAs appear to respond to market forces, and at least half change to another specialty during the span of a career, which may contribute to their satisfaction.25
The ability to change specialties suggests that mobility and adaptability could be vocational characteristics that contribute to retention. Furthermore, procedural-based specialties coupled with physician shortages tend to attract PAs. This finding may be due to high salaries associated with labor-intensive specialties.26,27
Finally, traditional retirement patterns are changing and seniors are using bridging strategies to remain at least partially involved in their career into their 70s, a trend that may be rising but is difficult to calculate.28
The supply and rate of growth of PAs in the U.S. medical workforce has significant policy implications given the reliance that is placed on them to supplement the predicted shortage of physicians.5
The projected growth will result in 72% more PAs by 2025, but will likely only provide 16% of the providers needed to address the projected primary care physician shortage, unless additional policies are instituted to increase the number of PA graduates and/or incentivize PAs to practice in primary care.6
Instituting policies that encourage the -development of new PA training programs holds potential for addressing some of the primary care physician -shortage. Expanding the number of graduates per program appears to be the change with the greatest likelihood of increasing the number of PAs by 2025. This increase could be accomplished through policies that provide funding for clinical preceptor sites, thereby addressing the biggest limitation in PA program expansion.
There is also the potential for PAs to make increased contributions to primary care delivery through policy initiatives. For example, §5501(a) of the Patient Protection and Affordable Care Act provides for an incentive payment for PAs for whom primary care services accounted for a majority of their service provision.29
As with any modeling exercise, the projections depend on the variables, parameters, and estimates used. For example, there was no information on the retirement pattern of nonfederal PAs. Thus, the rate of attrition calculated may be subject to some margin of error. Additionally, there are no details about role delineation and what percentage of PAs has daily patient contact. These limitations spotlight the need for better data that a longitudinal cohort analysis could bring. Qualitative analysis of career satisfaction, job mobility, and retirement goals could provide needed insight into occupational stability.
Also, while the predictions have the appearance of accuracy, there are too many variables to achieve such precision over long periods of time in modeling. Furthermore, forecasts are vulnerable in the adequacy of model documentation, the frequency of model maintenance, the existence of evaluative information on model validity, and the quality of model data. Triangulating census data with state licensure data would provide some confidence in the numbers, although even this methodology has problems of uniformity.30
Adherence to the intent of the National Provider Identifier would improve annual estimates of care by different providers.
This study also had several strengths. One strength of this study was that we drew on a suite of refined and reliable databases that complement one another. High participation rates in the annual PAEA surveys and NCCPA data incorporated in this study also contributed to the confidence of the numbers. The release of confidential program development data from ARC-PA added substantial value to the predictive model. Finally, previously unknown annual noncertification rates from the NCCPA permitted refinement of projections.