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Physician Workforce

PERSPECTIVE

New Opportunities For Old Mistakes

Morris Barer

The assumption that historical supply reflects demand (running from demand to supply) simply ignores the fact that physicians have considerable influence over both what services they provide and the other health care services "demanded" by patients. Also ignored is the potential of new technologies to enhance productivity, as they do in other sectors of the economy. By embracing the view that what goes on in health care is largely due to "exogenous trends" and that "simpler and more aggregate models are more effective and readily reproducible," the authors are thereby able to dispense with the inconvenience of having to collect or consider a lot of detailed data or attempting to understand the dynamics of physician service provision. Unfortunately, the devil is in the detail, and much of what goes on in health care systems everywhere is, in fact, quite endogenous.

The authors’ approach of projecting the future demand for physicians on the basis of a historical relationship between physician supply and economic growth hinges critically on the key assumption that "historical trends in physician supply reflect the historical demand for physician services."² Furthermore, by focusing on (without adequately defining or being able to measure) "demand" as the relevant measure for future planning, the authors are able to stickhandle around the awkward matter that "needs," "capacity to benefit," and "appropriateness of care" might be of some importance in any consideration of future physician requirements.³ By obfuscating these conceptual distinctions, they are able to ignore the compelling and substantial body of evidence that significant amounts of health care—at times ranging as high as 50 percent—have turned out to be unnecessary or inappropriate.⁴ Further, although Cooper and colleagues incorporate the impact of physician substitutes in their future "demand" projections, the supply-demand link implies that all services provided by physicians over the long historical sweep needed to be provided by physicians; that is, that any and all substitution potential had been wrung out. Here again this would seem to fly in the face of a substantial body of countervailing evidence, some important parts of which have been penned by one of the paper’s authors. Simply assuming exogeneity of the key factors underpinning supply growth, and therefore of demand for physician services (it’s the economic growth, stupid), avoids these sorts of unseemly complications. Yet if taken into account, they would create a quite different historical picture, and all projections are critically sensitive to their points of departure.⁵

The assumption that demand has historically driven supply is perhaps most tellingly exposed by recalling a bit of Canadian history. In 1964 a Royal Commission chaired by then Justice Emmett Hall produced a landmark study on the future of Canadian health care.⁶ This study provided the blueprint for the uniquely Canadian universal first-dollar public financing of hospital and medically necessary physician services. Among its many recommendations was a dramatic expansion in domestic training of physicians, to address the assumed increased "demands" associated with moving to first-dollar coverage and, more importantly, the need to maintain a stable physician-to-population ratio in the face of rapid future population growth.⁷

In less than a decade it had become clear to any who bothered to look that the population projections on which Hall had based his medical school expansion recommendations were seriously out of whack. By 1991 Canada’s population was almost 25 percent lower than Hall had projected.⁸ Nevertheless, the expansion stuck, and physician supply in Canada for the past three decades has been heavily influenced by the training machinery that was put in place in response to that recommendation. Cooper and colleagues are asking us to believe that these Canadian "historical trends in physician supply reflect the historic demand for physician services," when in fact a huge segment of the expected source of "demand" simply never showed up.

If demand for physician services is integrally linked to economic expansion over the long haul, we might expect to find that the sustained economic downturn in Russia and central and eastern Europe had reduced demand for physician services despite reduced life expectancy and increased rates of ill health.⁹ Indeed, should the current economic slowdown in the United States become prolonged, as in Japan, the "demand" for physician services would, on this model, be expected to flatten or fall, despite ample evidence of a strong link between unemployment, health status, and mortality rates.¹⁰ It is quite possible that such circumstances might be associated with reduced "demand" for physician services but increased "needs" for those same services.

Like many economic models, this one has the virtues of simplicity, surface plausibility, few data requirements, and ease of use. But it also shares another key attribute of all economic modeling: The results or implications of the model are only as good as the assumptions on which it is built. The United States may, indeed, be facing a future shortage of physicians. Whether that is the case, and if so the magnitude of any such shortage, cannot reliably be discerned from this model. Like a model car, it looks good until you try to drive it.

Editor's Notes

 
Morris Barer is scientific director, Institute of Health Services and Policy Research, Canadian Institutes of Health Research, and professor, Centre for Health Services and Policy Research and Department of Health Care and Epidemiology, the University of British Columbia in Vancouver.

This paper reflects the improving suggestions on an earlier draft from Bob Evans and Diane Watson.

NOTES

Top NOTES

 

1. J. Lomas, G.L. Stoddart, and M.L. Barer, "Supply Projections as Planning: A Critical Review of Forecasting Net Physician Requirements in Canada," Social Science and Medicine 20, no. 4 (1985): 411–424; J. Lomas, M.L. Barer, and G.L. Stoddart, Physician Manpower Planning: Lessons from the Macdonald Report (Toronto: Ontario Economic Council, 1985); and R.G. Evans, "New Bottles, Same Old Wine: Right and Wrong on Physician Supply," Canadian Medical Association Journal 158, no. 6 (1998): 757–759.[Medline]
2. One need only recall the long-standing "tight" relationship between the percentage of gross domestic product (GDP) spent on health care in Canada and the United States through to about the early 1970s (R.G. Evans, "Adapting to Adversity, Protecting the Principles, Resisting Reactionary ‘Reforms’: Canada’s Health Care System in the 1990s" [Vancouver: UBC Centre for Health Services and Policy Research, HPRU 97:9D, 1997]) to realize how precarious is a model based on presuming the continuation of historical correlations. And the source of the departure from that particular stable relationship was the endogeneity of the factors driving health care system use.
3. This sleight of hand is enabled through a decision to eschew consideration of "what ought to occur" in favor of "what [is] most likely to occur." If all the key parameters are exogenous, "what ought to occur" is out of our hands, so why bother our minds (or our models) with it?
4. M.A. Schuster, E.A. McGlynn, and R.H. Brook, "How Good Is the Quality of Health Care in the United States?" Milbank Quarterly 76, no. 4 (1998): 517–563[Medline]; and J.M. Lavis and G.M. Anderson, "Appropriateness in Health Care Delivery: Definitions, Measurement, and Policy Implications," Canadian Medical Association Journal 154, no. 3 (1996): 321–328.[Abstract]
5. Projections of the impact of an aging population on requirements for hospital care, for example, ran rather afoul, somewhere over the long sweep, of endogenous system factors that resulted in a significant reduction in hospital capacity throughout the industrialized world. R.G. Evans et al., "Apocalypse No: Population Aging and the Future of Health Care Systems," Canadian Journal on Aging 20, Supp. 1 (2001): 160–191.
6. E.M. Hall, chairman, Report of the Royal Commission on Health Services (Ottawa: Queen’s Printer, 1964).
7. Interestingly, the stable physician-to-population ratio to which the authors aspired was 1:857.
8. M.L. Barer and G.L. Stoddart, "Toward Integrated Medical Resource Policies for Canada: 7. Undergraduate Medical Training," Canadian Medical Association Journal 147, no. 3 (1992): 305–312.[Medline]
9. See, for example, C. Hertzman, A. Siddiqui, and M. Bobak, "The Population Health Context for Gender, Stress, and Cardiovascular Disease in Central and Eastern Europe," in Heart Disease: Environment, Stress, and Gender, ed. G. Weidner, M. Kopp, and M. Kristenson (Amsterdam: IOS Press, forthcoming), published in cooperation with NATO Scientific Affairs Division; B.P. Kennedy, I. Kawachi, and E. Brainerd, "The Role of Social Capital in the Russian Mortality Crisis," World Development 26, no. 11 (1998): 2029–2043; and C. Hertzman, S. Kelly, and M. Bobak, eds., East-West Life Expectancy Gap in Europe: Environ-mental and Non-Environmental Determinants, NATO Advanced Science Institute Series 2: Environment, Vol. 19 (London: Kluwer, 1995).
10. J.N. Lavis, "Unemployment and Mortality: A Longitudinal Study in the United States, 1968–1992," Centre for Health Economics and Policy Analysis (CHEPA) Working Paper 98-5 (Hamilton, Ont.: McMaster University, 1998); M. Bartley and C. Owen, "Relation between Socioeconomic Status, Employment, and Health during Economic Change, 1973–93," British Medical Journal 313, no. 7055 (1996): 445–449[Abstract/Free Full Text]; and M.E.J. Wadsworth, S.M. Montgomery, and M.J. Bartley, "The Persisting Effect of Unemployment on Health and Social Well-Being in Men Early in Working Life," Social Science and Medicine 48, no. 10 (1999): 1491–1499.

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