VIII.  Conclusions

A. Summary

An adequate supply of physicians is needed to help ensure access to affordable, quality care. Over the past 70 years since the Committee on the Costs of Medical Care (CCMC, 1933) conducted the first major scientific study of the adequacy of physician supply in the United States, the approach to modeling physician supply and demand has evolved to reflect improvements in our understanding of the determinants of physician supply and demand, improved data collection, and improved analytical techniques.  Still, workforce modeling remains as much art as it is science.  As stated by Uwe Reinhardt (2002): 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 (p. 196).” This is especially true when projecting demand for physician services, where there is much uncertainty regarding the characteristics of the future health care system.

While there is generally consensus with physician supply projections, physician requirements projections are often controversial.  The lack of consensus on requirements projections reflects differences in assumptions about the major determinants of demand for physician services, incomplete information on future trends in health care utilization and delivery of services, different but valid approaches to modeling future requirements, and philosophical differences on the definition and purpose of requirements projections.

HRSA’s Physician Supply Model and Physician Requirements Model, like all models, are simplified versions of a complex health care system that generalizes the millions of decisions made by physicians, patients, insurers, and other entities into probabilities that certain events will occur based on historical patterns of behavior.  As stated by Ehrenberg and Smith (1991, p. 5), "models are not intended to capture every complexity of behavior; instead, they are created to strip away random and idiosyncratic factors so that we can focus on general principles."  The PSM and PRM attempt to capture these major factors as identified based on theory, a review of the literature, and original analysis.  The major trends with implications for the physician workforce include:

• Changing demographics.  The U.S. population is growing, aging and becoming more racially and ethnically diverse.  The physician workforce is also aging, and women constitute a growing proportion of physicians.
• Rising cost of government programs for the elderly.  The aging population will place increasing cost pressure on State and Federal government retirement plans and social programs that serve the elderly (e.g., Medicare, Medicaid, and Social Security).
• Increased cost consciousness.  Rising health care costs is spurring efforts by insurers to find new ways to contain costs.
• Economic growth.  Increased prosperity has the potential to increase public expectations and demand for physician services.
• Proliferation of health care specialties—including nonphysician clinicians.  The past few decades have seen a proliferation of health care specialties—both within the physician community and among NPCs—which both increases competition among health care providers but also provides patients with a broader range of health care services.
• Scientific and technological advances.  Technological breakthroughs continue to change both demand for health care services and the way in which services are delivered.

For this study we computed a range of supply and requirements projections for scenarios reflecting different assumptions about the future health care system, the evolving role of physicians, and trends in other supply and demand determinants.  The baseline projections assume that over the next 1 to 2 decades things will continue largely as they are.  The Nation will continue to graduate a slightly growing number of new physicians, health care utilization and practice patterns will reflect current patterns, and the main driver of changing demand for physician services is the growth and aging of the population.  Alternative supply and demand scenarios model the sensitivity of projections to these assumptions, as well as reflect differences in the literature on the main determinants of physician supply and demand.

The baseline projections suggest that overall demand for physician services is growing faster than supply.  Without a modest increase in number of new graduates from U.S. medical schools, the Nation cannot continue to provide the same level of health care unless the health care system becomes more efficient at delivering care traditionally provided by physicians; reduces demand for physician services through improved science, technology, or use of other inputs to care; or becomes more dependent on foreign-trained physicians.

B.  Policy Implications

The Federal Government, as a major player in the health care system via its role as health care insurer, subsidizer of physician training, and role to improve access to care to underserved populations has often exerted its influence in an attempt to create a coherent national workforce policy and to improve access to affordable, quality health care.

The modest but growing projected shortfall of physicians could impede national health care goals, if left unchecked, by contributing to greater geographic disparities in physician supply.  For several decades the United States  has been a net importer of medical school graduates.  A growing demand for physicians that exceeds production from U.S. medical schools could make the Nation even more reliant on international medical schools, and this at a time when other nations face greater health workforce inadequacies.

As the population ages and places greater pressures on the health care system, economic realities will require some form of cost containment.  Because physicians directly account for an estimated 20 percent of health care expenditures and indirectly account for the majority of health care spending, any attempt to control health care costs will directly affect physicians.

C.  Areas for Future Research

Although the physician workforce literature continues to grow, there is still a need for additional research on the relationship between physician supply and its determinants, and between physician requirements and its determinants.  Lack of data continues to be a major hindrance to conducting research on physician behavior and how practice patterns change over time and in response to changes in the health care operating environment.  The high cost to collect such data in a timely and consistent manner requires collaboration on the part of payers, provider associations, researchers, and Federal and State stakeholders.

The health care system continues to evolve as does the role of physicians.  Because of the long length of time needed to train physicians and to change the education infrastructure, policymakers, educators, physicians, and other stakeholders need to know at least a decade in advance how changes in the health care system and other trends will affect the adequacy of physician supply.  Physician supply and demand projections should be updated every few years to reflect the latest trends and to provide this advance warning of changes in the adequacy of physician supply.

Finally, it should be remembered that the physician workforce is only one part of an increasingly complex health care system in which the final goal is a healthier society.  The link between number and type of physicians, as well as the content of their education, and the health status of the populations they serve has yet to be completely understood.  Further investigation regarding the impact of the physician workforce on health will better inform workforce planning.