While most doctoral students rely primarily on some combination of grants, teaching assistantships, and research positions to cover tuition and living expenses, they also often use personal savings, spouses’ earnings, and student loans. Consequently, more than 12 percent of all Ph.D.s complete their doctoral programs with over $70,000 of combined undergraduate and graduate student-loan debt. Rates are especially high in the social sciences and education. Those debt levels are alarming, especially because fewer students have jobs lined up immediately after graduation than was the case 10 years ago.

The job market for those with advanced degrees is clearly tightening, according to the NSF study, with many more Ph.D.s in all fields reporting no definite job commitments in 2014 compared to 2004. Nearly 40 percent of the Ph.D.s surveyed in 2014 hadn’t lined up a job—whether in the private industry or academia—at the time of graduation.

It may not be surprising that Ph.D.s in the humanities and social sciences are struggling to find tenure-track faculty jobs. After all, graduate schools produced two new history Ph.D.s for every tenure-track job opening in 2014. However, with the heavy push towards STEM at universities and opportunities for positions in the private industry, the employment woes for engineering and science Ph.D.s are puzzling.

Ph.D. graduates who reported that they had accepted positions found work in the private industry, academia, or as post-docs. Most Ph.D.s in the humanities, education, and social sciences who have secured plans will work in academia—but the report does not indicate whether they are employed in tenure-track positions, in non-tenure track jobs, or as temporary adjunct jobs, which have grown in popularity in recent years.

A Ph.D. who wins the rare job as a tenure-track professor earns on average about $60,000 per year, according to the NSF report. In contrast, post-doc positions—temporary research spots that are most common in the sciences and draw 39 percent of the Ph.D.s with post-graduation commitments at universities—pay a little over $40,000 per year. Incidentally, the median entrance-level salary for college graduates with a B.A. in 2014 was $45,478.

It’s unclear what happens to the 40 percent of Ph.D.s who don’t get a job of some sort—even of the post-doc variety—after graduation. Perhaps some move onto other professions after a year or so. Maybe some work for peanuts as adjuncts. Others may rely on their partner’s income. What’s more, as Inside Higher Ed’s Scott Jaschik notes, the tightening job market means increases in job-market competitiveness, as new Ph.D.s must compete for positions not only with their own cohort but also with the unemployed Ph.D.s. who graduated in previous years.