There is an outcry in the United States that we’re facing an urgent nurse deficit that threatens the safety of individual patients and the nation’s health as a whole. Consider arguments from two Times editorials. “The nationwide shortage of nurses is likely to reach crisis proportions.... There is not much chance for permanent relief until the nursing profession is made more attractive to young people through better salaries, working conditions and public recognition,” one reads. In another, titled “We Need More Nurses,” Alexandra Robbins warns of dire consequences in the absence of a larger nursing workforce: “The more patients assigned to a nurse, the higher the patients’ risk of death, infections, complications, falls, failure-to-rescue rates and readmission to the hospital—and the longer their hospital stay.”

Robbins’s article was published this May. The first, however, was published in 1965. Is it really possible that the United States has not had enough nurses for half a century? As evidence for their arguments, medical groups tend to tout quantitative research—one 2012 study, for example, projects shortages reaching as high as seven figures between now and 2030, with especially acute gaps in the South and the West. But another article, published the same year in the New England Journal of Medicine, noted that during the eighteen-month recession that began in December, 2007, the United States economy as a whole lost 7.5 million jobs, while hospital employment of registered nurses showed its biggest gain in four decades. The authors even asked if we are experiencing a nursing “bubble.” Ultimately, though, they too concluded that shortages will recur.

The seeming intractability of this problem is highly unusual. In a relatively free society and economy, the tendency with any labor-supply shortage, in the face of steady or increasing demand, is that higher wages and other benefits will attract people to the profession, and the problem will largely resolve itself over time. Why has this not been the case with nursing?

There are about 2.7 million registered nurses working in the United States, according to the Bureau of Labor Statistics. One of the primary challenges, both in measuring whether we have enough nurses and whether they work where they’re needed, and in figuring out how to retain them, is that the nursing workforce is relatively volatile. A 2010 government survey found that nearly half a million licensed nurses weren’t working in the field.

Some of these problems begin with training. As both Times editorials suggest, nursing is very demanding, and the education required is rigorous, in terms of both its duration and the level of specialized knowledge required. For those who are prepared to commit, there is a shortage of clinical-training slots, and of teachers. Generally speaking, those who are qualified to teach and train nurses can make more money by actually working as nurses. According to one report, last year seventy-eight thousand applicants to nursing programs were turned away because there were not enough teachers for them.

For those in the field, the work is difficult enough that a large percentage of nurses leave the profession at some point in their careers. Anyone who knows a nurse has probably heard some scary stories about getting jabbed with needles or attacked by patients. While nurses tend to be satisfied with their career choice, fully half of them worry that the job has harmed their health. Some surveys of nurses have also found dissatisfaction with wages, hours, technological complexity, and administrative burdens. Academics describe the nursing workforce as “countercyclical,” meaning that nurses tend to enter the labor market when the overall economy is doing poorly, and to leave the market when the economy is better. One reason for that pattern, according to the authors of the N.E.J.M. article, is that the nursing workforce consists overwhelmingly of married women. Registered nurses “who were not working or were working part-time may rejoin the workforce or change to full-time status to bolster their household’s economic security,” they write.

Moreover, there are also large regional discrepancies in where nurses are concentrated—and those discrepancies appear to be heightening over time. A 2012 article in the American Journal of Medical Quality assigned a letter grade to each state based on its nursing shortage as of 2009 and its projected nursing shortage for 2030. For 2009, only two states—Massachusetts and South Dakota—received an A. In the 2030 projections, there are no As, and twelve Fs, heavily concentrated in Western states.

The very idea of such grades, of course, presumes that someone knows what the “right” number of nurses is. The article calculated its grades based on the number of standard deviations from the national average, which, in 2009, resulted in the number eight hundred and forty-four nurses per hundred thousand population. But, as one of its authors acknowledged in an interview, “it’s really difficult to pin down what the ideal ratio is.” A federal law requires “adequate” nursing staff at any hospital that participates in Medicare, but the term is not defined. Some states have laws requiring a certain ratio of nurses to patients in particular health-care sectors, but most do not regulate the issue at all.

The perpetual nature of the crisis, and the projections moving forward, naturally lead to the question of whether, given our evolving awareness of the underlying complexities, different policies can hope to create more nurses. These types of mismatches between skills and demand are supposed to be what markets solve. Of course, the market may be making adaptations that are harder to measure. Some medical professionals suggest that the health-care system has reduced its need for nurses by assigning some tasks to other types of workers, such as nursing assistants, technicians, and orderlies. Such shifts may or may not be welcomed by nurses themselves and could also involve compromises in the quality of care. A better alternative, however, would be to improve the ways we attract and train nurses. That means increased emphasis on building hospitals and unblocking the education bottleneck. With those tasks, the market may need a little help.