Salsberg points out, tend to use more health-care resources than other segments of the population. He also adds that in 2020, baby boomers will just be starting to turn 75.

Another factor in the AAMC's stance is the change in lifestyle choices being made by younger physicians. Salsberg predicts that as new doctors fill the workforce, they will have different expectations about the demands of the job. Dr. David Nierenberg, the senior associate dean for medical education at DMS, agrees. "I believe the AAMC is right that we are going to need more doctors," he says. "Doctors today—and this is probably a healthy thing—no longer want to work 80-hour weeks. They want to work 40- or 50-hour weeks."

In 2005, to address these concerns, the AAMC issued a position statement calling for a 15% increase in medical school enrollment over 2002 levels by 2015; it has revised that position and now calls for a 30% increase to avoid what it predicts could be a shortfall of 124,000 physicians by 2025. COGME likewise called in 2005 for a 15% increase in medical school enrollment.

Goodman argues that the methods used by the AAMC are fundamentally flawed. "The AAMC's projection models are what I would call quantitative slogans," he says. "They're all based on the notion of replicating today's health-care system and labor market into the future at a time when everyone agrees that the last thing that we want is just to simply perpetuate the health-care system."

As the AAMC and COGME began warning of the potential physician shortage, Goodman accumulated evidence pointing to the opposite conclusion. It's not a question of demographics, he says. The issue is "how populations are affected by physician supply and by growth in physician supply." In place of projections,

Goodman cites research showing that beyond a certain point, the number of physicians has little to do with quality of care.

In a 2006 study, for example, Goodman examined differences in end-of-life care at 79 academic medical centers and found enormous variation in the amount of care provided to patients during the last six months of life. The amount of physician labor dedicated to each patient at the most-care-intensive hospital—New York University Medical Center—was 4.7 times higher than the amount at the least-care-intensive hospital—Medical College of Georgia. The study accounted for factors such as age, race, and gender and looked only at patients admitted for one of 12 chronic conditions. So, Goodman argued, the variation could not be explained by differences in the patient population. Rather, some hospitals simply provided more care without improving patient health.

As further evidence, Goodman noted that the differences mirrored regional variations in Medicare spending per patient. That is, centers that expended more physician labor were located in

regions with more-costly patterns of care. For example, Manhattan patients generally—not just chronically ill patients at NYU Medical Center—were likely to receive relatively intensive care.

Goodman uses studies such as this one to make the case that the problem isn't a lack of doctors—it's how those doctors are used. In a 2006 op-ed essay in the New York Times, he wrote that if the ratio of doctors to patients at NYU was used as a benchmark for the entire country, an additional 44,000 doctors would be needed by 2020 just to care for the elderly. But, he added, if the ratio at more efficient medical centers—such as the Mayo Clinic in Rochester, Minn.—was used as a benchmark, then there would be a surplus of about 50,000 doctors by 2020.

In another study, Goodman examined the relation between the supply of neonatologists and infant mortality. Using data from the mid-1990s, he found that the number of neonatologists per 10,000 live births varied by region from 2.7 to 11.6, but once the supply reached 4.3, there was no further improvement in the mortality rate. Increasing the number of these specialists did not lead to fewer deaths. If that's the case, Goodman says, why continue to increase the supply? "Is that going to help babies?" he asks.

In talking about the physician workforce, Goodman always returns to the basic goal of health care: to improve the health of patients, not just to deliver care. He realizes it can be hard, especially for doctors, to accept the notion that increasing the physician supply might not do much to meet that goal. "If the number of doctors isn't all that important, I mean, that's not welcome news," he admits. He emphasizes, however, that he offers his criticisms as a fellow physician. "I am a physician, I'm at a teaching hospital, obviously, and I am part of academic medicine," he says.