Summary
The growth and aging of the United States
population will cause a surge in demand for physician services.
If current healthcare utilization and delivery patterns
continue, the overall supply of physicians should be sufficient
to meet the expected demand through the next 10 years. This
finding suggests the need for modest increases in United
States medical school capacity. Currently, one in four physicians
in a residency programs graduated from a foreign medical
school, and a large portion of IMGs remain in the United
States after completing their graduate training. If the
United States desires to rely less on IMGs to meet the growing
demand for physician services, then United States medical
school capacity must be expanded beyond the expansion necessary
to meet the needs of a growing and aging population. The
baseline projections suggest the possibility of�future realignments
in graduate medical training, expanding the number of physicians
trained in some specialties (e.g., general surgery, urology,
ophthalmology, cardiology, pathology, orthopedic surgery,
other internal medicine subspecialties, otolaryngology,
radiology, and psychiatry).
[D]
Models
to project physician supply and demand are often sensitive
to assumptions regarding the characteristics of the future
healthcare system and whether current trends will persist.
Replete with examples of projected trends that failed to
fully materialize and the emergence of trends that were
never anticipated, the history of the United States healthcare
system shows a system that is continually evolving. As Uwe
Reinhardt (2002, p. 196) states: it is a “daunting
enterprise . . . to estimate the physician surplus or shortage
one or two decades into the future. Any of the variables
in the equation can change over time, sometimes in unforeseen
ways.” This fact is especially true when projecting
demand for physician services, where much uncertainty exists
regarding the characteristics of the future healthcare system.
Factors
leading to potential underestimates of physician requirements
include: (1) underestimates by the United States Census
Bureau of actual population growth, (2) overestimates of
the proportion of population insured through plans with
aggressive managed care practices, (3) overestimates of
proportion of care provided by NPCs, (4) underestimates
of increased per capita use of physician services over time,
and (5) overestimates of increases in physician productivity.
Although we are unable to predict with certainty whether
current trends in the healthcare operating environment will
persist and what new trends will emerge, efforts to model
physician supply and demand require educated predictions
of major trends that affect the physician workforce. These
uncertainties, combined with an ever changing healthcare
system, highlight the need to frequently reassess supply
and requirements projections.
In addition
to the uncertainties mentioned above that affect the accuracy
of projections, the PSM and PRM, like all projections models,
have their limitations. For example, both models are static
in that they do not model how physicians, patients, and
insurers will react to changing conditions. As an example,
physician earnings tend to increase as demand exceeds supply,
resulting in financial incentives for physicians to enter
specialties with a shortage of physicians rather than entering
specialties with a surplus of physicians. Similarly, the
scope of practice in particular specialties is changing
over time. An expanded scope of practice could result in
greater physician requirements for that specialty, with
the possibility that requirements might fall for a specialty
with an overlapping scope of practice that competes for
many of the same patients.
A limitation
of a utilization-based approach to model physician requirements
is that, by definition, the approach assumes that the physician
labor market is in balance in the base year. Inefficiencies
in the delivery of care are extrapolated into future years’
projections.
Another
limitation is that the PSM and PRM are national models.
Although they can be adapted to project supply and demand
for smaller geographic regions such as States, the models
do little to inform the debate regarding the future adequacy
of physician supply in currently underserved areas. Past
government policies to improve physician supply in underserved
areas have relied in part on the assumption that physician
surpluses (especially surpluses of primary care physicians)
will create financial motivations for physicians to gravitate
to underserved areas. The baseline projections suggest that
the supply of primary care physicians will grow at about
the same rate as demand through 2020, which will create
little financial pressure for primary care physicians to
disperse to traditionally underserved areas.
Additional
research that might improve the supply projections include
the following:
· Estimating
more exact retirement patterns. As discussed, the PSM uses
historical data to estimate separation rates that we think
reflect long-term trends, rather than short-term fluctuations
reflecting current market conditions. Preliminary results
from the PWS are consistent with the concern that AMA Masterfile
data underestimate the number of retired physicians, which
could lead to overestimates of physician supply.
· Modeling
specialty choice. The PSM uses historical data to estimate
the distribution of new physicians into various specialties.
This reliance on historical data might understate the importance
of new trends in specialty choice—especially as it
pertains to relatively new specialties such as critical
care.
· Estimating
long-term trends in physician productivity. With the exception
of modeling trends in average hours worked as women and
older physicians constitute a growing portion of the physician
workforce, the PSM does not explicitly model changes in
physician productivity. We calculated the productivity scenario
presented in this paper outside the model and assumed a
1 percent annual increase in physician productivity. Improved
training, technological advances, and increased use of NPCs
and other health workers could lead to increased productivity,
and additional research could inform how such productivity
increases should be incorporated into the physician supply
projections.
Additional
research that might improve the demand projections includes
the following:
· Estimating
the impact of economic growth on physician requirements.
Economic growth could change patient expectations and the
ability of patients, employers, and the government to purchase
additional physician services. The recent work by Cooper
et al. has opened the debate on this topic, but the research
community is far from reaching a consensus on the implications
of economic growth for the future adequacy of physician
supply.
· Estimating
the impact of growing NPC supply on physician requirements.
Expansion of the clinical or business autonomy of NPCs could
increase competition between NPCs and certain physician
specialties, resulting in slower growth in physician requirements.
Similarly, collaboration between NPCs and supervising physicians
can increase physician productivity, which in turn reduces
physician requirements.
· Estimating
the impact of new technologies on short-term and long-term
requirements for physicians. New technologies could allow
physicians to provide new services, and they could reduce
mortality, increasing long-term requirements. Likewise,
new tests, procedures, pharmaceuticals, or equipment could
provide a substitute for some physician services thus slowing
the growth in physician requirements.
Despite
the limitations of projection models like the PSM and PRM,
and despite the uncertainties of how the healthcare system
will look in the future, these two models are powerful tools
for understanding the implications of changing demographics,
changing government policies, and other trends on the future
adequacy of physician supply. |