The U.S. physician workforce: serious questions raised, answers needed.

Answers Needed We all have a stake in the size of the physician workforce. With too few physicians, access to care will be compromised; with too many, there will be strong pressures to overconsume health services. Increasing the production of U.S.-trained physicians by expanding physical resources of medical schools and creating new residency and fellowship positions will be costly and will have delayed, long-lasting effects on the supply of physicians’ services. According to those who believe that physicians increase the demand for their own services, every additional physician would generate added health care costs for the length of a career, which now averages about 30 years. These increased expenditures would dwarf the short-term costs of expanding our capacity to train physicians. Because new graduates are a small fraction of the total physician workforce, the supply of physicians would change little in the short run, even if it were possible to expand the number of training positions instantly. In an article in this issue (1), Richard Cooper forcefully argues that this delay is an important reason to take immediate action to increase the production of physicians. He projects that the United States will have 200 000 fewer physicians than we need in 2020. We agree that demographic and economic trends could increase the demand for physician services in the coming years, but we also believe that his forecast contains far too many uncertainties to serve as the basis for taking immediate action. We think that Cooper’s analysis does not take account of important factors that could change the need for large increases in physician supply. In this commentary, we discuss the potential roles of a healthier aging population, changes in government policy, new technology, physician-induced demand for health care, and changes in the price of health care. Cooper’s concerns about future shortages rest on the conviction that both an aging population and rising economic well-being will increase the demand for physician services (2). A large literature reinforces Cooper’s claim that a nation’s economy drives its demand for health care (3, 4). Furthermore, in the United States and other nations, health expenditures and the number of physicians increase as the economy expands. Cooper bases his projection of a physician shortage of 200 000 largely on the historical relationship between the size of a nation’s economy and the size of its physician workforce. He implies that this historical relationship is the “right” one for maximizing the health of the nation. He seems to believe that the past relationship between the number of physicians and national wealth (“what is”) is “what ought to be” in the future. Cooper’s model for predicting future physician requirements treats the critical determinants of the “right” number of physicians as a black box. His model, like many others, fails to distinguish between the supply of and demand for physician services, and it fails to recognize the important role of price. People who can’t agree on the definition of the “right” number of physicians can agree on the “wrong” number: one that causes either shortages or surpluses of health care. People use the terms “shortage” and “surplus” loosely, but the standard economic definitions are clear: A shortage exists when there is unsatisfied demand, which occurs when the quantity of a good or service supplied is less than what people would be willing to buy at the current price. Long waits for elective procedures and for office visits are manifestations of shortage. Conversely, a surplus occurs when there are more willing sellers than buyers at the current price. Unless the demand for physician services is completely independent of price, describing a quantity as too low or too high has no meaning except in relation to its price. The debates about the adequacy of the physician workforce have largely failed to consider price along with quantity. Thus, to address future workforce needs, we must ask how demand and supply will each change and whether price shifts will prevent shortages and surpluses from developing. Although Cooper’s belief that economic forces increase the demand for physician services has considerable support from published research, other factors may reduce demand. A particularly important unknown is whether future cohorts of elderly Americans will have as much disease and disability as past cohorts. According to some evidence, older people are healthier (5, 6) and less disabled (7) than in the past. Changes in health care financing may also change the future demand for physician services in ways that we cannot fully anticipate. The effect of technologic innovation is probably the most important unknown in projecting future demand for physician services. New health technology could increase or decrease the demand for physician services. For example, a new operation would require a surgeon to perform it, which might increase the demand for surgical services—at least in the short term. But in the long term, the new procedure could obviate the need for other forms of medical care, leading to an overall reduction in the demand for physician services by substituting for them. The direction and nature of technologic change are not entirely predictable, but inventors and investors everywhere are aware of the large financial rewards awaiting breakthroughs in prevention and treatment of diseases. Some of their innovations will probably reduce rather than increase the need for physician services. With the explosion of genomics and biotechnology and other technologies, we shouldn’t simply use the historical effect of new technology on demand, as Editorial