For the overwhelming majority of Ph.D. holders who do not become tenured professors, spending time as a postdoc comes at a hefty price. Compared with peers who started working outside academia immediately after earning their degrees, ex-postdocs make lower wages well into their careers, according to a study published today in Nature Biotechnology. On average, they give up about one-fifth of their earning potential in the first 15 years after finishing their doctorates—which, for those who end up in industry, amounts to $239,970.

The financial sacrifice begins during the postdoc. As detailed in the new report, which uses National Science Foundation data to track the careers of thousands of people who earned Ph.D.s between 1980 and 2010, a typical postdoc in biomedicine lasts 4.5 years with an annual salary of about $45,000—as compared with the $75,000 or so paid as a median starting salary to Ph.D.s in industry. Biomedical postdocs who later enter the nonacademic workforce then face a pay gap that closes only after another 8 or 9 years. That’s evidence that a postdoc has little value outside of academia, says lead author Shulamit Kahn, an economist at Boston University.

“When you enter the job market at the end of a postdoc, you’ve essentially lost those years,” Kahn says. “You’re starting out at an entry level because a postdoc just doesn’t count in the way that job experience counts.”

The new finding is hardly surprising in the wake of other work that has highlighted the perils of being a postdoc, such as the 2014 National Academies report noting that the “sacrifices” made by postdocs “are not compensated later in their careers.” Nonetheless, the new study “provides some good—if dismal—data to further confirm the picture that the production model for scientists is a disaster,” says Hal Salzman, a labor economist at Rutgers University in New Brunswick, New Jersey.

This type of information is particularly important given that many graduate students’ and postdocs’ perspectives about their careers are at odds with these economic realities. In a 2016 study, postdocs tended to correctly estimate the slim odds of landing a tenure-track academic position. But about three-quarters of postdocs in life sciences also believed that postdoctoral research was important for getting a job in industry and began postdocs with little intention of going into academia. The new study highlights the error of this approach. “If you’re thinking that a postdoc is a way to get a good job in industry, this research would suggest that you’re making the wrong choice,” Salzman says.

The new study does not, however, capture nonmonetary priorities postdocs may have, notes Henry Sauermann, a professor at the Georgia Institute of Technology in Atlanta who studies the scientific workforce and lead author of the 2016 paper. “The open question is, do postdocs get different jobs that provide different benefits that are not financial,” he says. “Many say they would be willing to take a lower salary to have freedom and continue to publish their research.”

But regardless of trainees’ motivations, the hard data provided in the new study will help graduate students think more carefully about their future, hopes Julia Lane, an economist at New York University in New York City. “They need more information about their earning potential,” she says. “They need to understand that a postdoc is essentially high-quality cheap labor for the machine that is modern-day science.”

Students are not the only ones who need to pay attention to the risks of being a postdoc, Kahn adds. “The people we really have to convince are the professors and the advisers in grant programs,” she says. “The advisers should say, ‘Look it’s in our best interest to have you as a postdoc, but it may not be in your best interest.’ It’s getting cut-throat out there.”