Currently many clinicians licensed and counted as primary care doctors actually work in hospitals, emergency departments, in research, or in public health, or may not take care of Medicare beneficiaries at all, Chang says. In some cases, they have gone on to specialize in other fields such as cardiology.
"In healthcare, we are trying to figure out how many primary care doctors are really in the U.S.," Chang explained. "We don't have a good number; based on estimates that are inaccurate. It may be more certain in some areas, than in others."
The number of U.S. medical school students going into primary care has dropped 51.8% since 1997, according to the American Academy of Family Physicians, which predicts a shortage of 40,000 family physicians in 2020.
Chang explains a key element in evaluating the number of physicians in which there is a projected "large shortage of general internists and family physician to care for a growing number of elderly patients."
The Dartmouth study offers a "cautionary note" that having more physicians trained in primary care in an area, by itself "does not ensure substantially lower mortality, fewer hospitalizations or lower costs."
That other cautionary tale in Chang's report involves the AMA data itself. As Chang and co-authors note in the report, "Despite a widespread interest in increasing the numbers of primary care physicians to improve care and moderate costs, the relationship of the primary care physician workforce to patient level outcomes remains poorly understood."
At issue is the AMA's data Masterfile Dataset of doctors who list themselves as primary care providers. The AMA data is the "most commonly-used national measure of primary care physician workforce," as Chang notes.