Letters to the Editor
To the Editor:
Mr. Salsberg’s recent article includes a critique of physician workforce projections that IHS Inc. prepared for the Association of American Medical Colleges (AAMC).1,2 As the projections’ author and drawing on experience authoring previous workforce projections for AAMC and the Health Resources and Services Administration (HRSA), which Salsberg cites, I offer responses to his criticisms.
These criticisms reflect, in part, differences in professional judgment or misunderstanding of assumptions underlying our projections. No matter how solid the data or rigorous the analysis, projections require assumptions to fill data and analytical gaps, which is why we produced projections in ranges.
- Salsberg notes that we acknowledged the importance of physician assistants (PAs) and their rapid growth in numbers but suggests that PAs were excluded from our projections. Our projections do assume that the approximately 100,000 PAs will continue to provide care—with 16,000 additional PAs needed between 2013 and 2025 to maintain current staffing ratios. Our projections omit the impact on physician demand of PA supply growth in excess of 16,000 because reliable PA supply projections by specialty were unavailable for this study.
- Salsberg observed that our projections assume 15,000 nurse practitioners (NPs) trained annually, yet notes that the American Association of Colleges of Nursing reports more than 18,000 trained in 2014. The 15,000 estimate reflects analysis of HRSA’s 2012 Nurse Practitioner Survey which found that not all NPs provide patient care or practice in positions requiring NP certification.
- There is little empirical evidence to suggest by how much the increased supply of PAs and NPs offsets physician demand. This is an important area for research, and the cited 75% substitution rate is subject to debate.
- Salsberg said the projections did not include reductions in physician demand due to “incentives for systems redesign, efforts to reduce readmissions, or the use of new technologies.” Despite their promise and substantial experimentation, the definitive effect of each has not been demonstrated. There were once widespread expectations that managed care and information technology would transform the delivery of health care. Both certainly have had an effect, but hardly a transformative one.
Overall, Salsberg says “there is evidence that shortages in the future are likely to be less than today’s shortages.” In my judgment, whatever evidence exists is inconclusive. Salsberg is correct that despite recent advances in workforce modeling, additional data and research are needed to continually improve the ability to project the future.
Timothy M. Dall, MS
Managing director, IHS Inc., Washington, DC; Tim.Dall@ihs.com.
1. Salsberg ED. Is the physician shortage real? Implications for the recommendations of the Institute of Medicine Committee on the Governance and Financing of Graduate Medical Education. Acad Med. 2015;90:1210–1214
2. Dall T, West T, Chakrabarti R, Iacobucci W. The complexities of physician supply and demand: Projections from 2013 to 2025. Prepared for the Association of American Medical Colleges. 2015 Washington, DC Association of American Medical Colleges https://www.aamc.org/download/426242/data/ihsreportdownload.pdf
. Accessed August 21, 2015