Merrill Goozner writes that a major expansion in our medical workforce, with a 30 percent surge in first-year medical school enrollment between 2002 and 2016, could spell bad news for our health care spending:

Health care reformers say the increased enrollment has not addressed the ongoing shortage of primary care physicians, especially in poor and rural areas, which will only grow worse when 30 million previously uninsured patients seek compensated care after 2014 because of the Affordable Care Act.

Meanwhile, cost-control advocates fret that the continuing migration of too many young physicians into highly paid specialties is contributing to the crisis in Medicare financing, which has been driven in part by overuse of expensive procedures.

There certainly is concern that America won’t have enough doctors to meet the predicted demand from the health reform law. But when you dig into the data of what careers young doctors are pursuing, it’s far from clear that there is a “continued” migration into highly-paid specialties. If anything, aspiring doctors look to be turning to the lower-paid, primary care specialities in growing numbers.

The National Residency Matching Program puts out data, each year, on what kind of residency programs doctors are matching into. In 2009, they saw something surprising start happening: After over a decade of decline, more and more students were applying for primary care residencies. Here’s what that looked like in family practice residencies:

Part of that is increased demand: As Washington has debated health reform and heard more rhetoric about the importance of primary care, medical students look to have become increasingly interested in those fields. There’s also a supply element, as the health reform law’s Primary Care Residency Expansion has added nearly 1,000 new residency slots in these fields.

Over the same time period, American medical students look to have become slightly less interested in specialty care. Matches into radiology programs — one of medicine’s most lucrative professions — bounced around in the late 1990s and early 2000s, before ticking downwards in the last few years:

Primary care physicians are arguably the doctors who can make medicine less expensive, rather than drive up costs. Most primary care doctors earn salaries about half that of the best-paid specialities, such as radiology and anesthesiology. These are also the doctors who tend to be on the frontlines of medicine, with potential to manage chronic conditions, such as heart disease or diabetes, before they manifest more complicated, and costly, symptoms.

It’s hard to deny that, as our population gets older and insurance expands, America is going to need more doctors. And we do have a lot fewer students than we did, in the late 1990s, interested in primary care. But if the numbers from recent years are any indicator, it looks like we’re training the doctors who are going to make our health care system cost less, rather than more.