If anything, the situation for underrepresented minorities is getting worse. Gibbs found that between 2005 and 2013, almost 6,000 scientists from those groups earned their doctoral degrees, while the number of assistant professors fell by six. “If you assume the system will take care of itself naturally as you diversify the talent pool, this calls that in to question,” he says.

“Saying that there are not enough applicants in the pool can no longer be an excuse,” says Mónica Feliú-Mójer, vice-director of Ciencia Puerto Rico, a non-profit that supports and mentors Latino scientists. “It hasn’t been for underrepresented minorities like me for a long time, but now there’s data to refute it. It provides validation to the many anecdotes from those of us working to enhance diversity in the biomedical workforce. I hope that this makes our work a little easier.”

But why does the gap exist? Donna Ginther from the University of Kansas wonders if it’s partly because Gibbs focused on medical schools, most of which do not guarantee salary with tenure, and so might be unattractive when compared to other alternatives. Perhaps scientists from minority groups are just seeking employment elsewhere. Gibbs counters that this is unlikely, since almost every sector of academia struggles with faculty diversity.

Hiring practices are a likelier culprit. As Marybeth Gasman, from the University of Pennsylvania, recently wrote in the Washington Post, “faculty will bend rules, knock down walls, and build bridges to hire those they really want (often white colleagues) but when it comes to hiring faculty of color, they have to ‘play by the rules.’” They start talking about “quality,” Gasman says, which typically means that “the person didn’t go to an elite institution for their Ph.D. or wasn’t mentored by a prominent person in the field”—opportunities that are often denied to people of color.

People of color are also more likely to drop out of the academic world. In an earlier study, Gibbs showed that women and underrepresented minorities are 36 to 54 percent less likely than white and Asian men to be interested in faculty careers, even after accounting for their publication record, their belief in their own abilities, and how interested they were when they entered their Ph.D. programs. That’s tragic. Regardless of their talent, confidence, and dreams, they were less likely to want to stay in research. “That suggests the environment isn’t one where all scientists feel they can contribute and thrive,” says Gibbs.

The neuroscientists Daniel Colon Ramos and Alfredo Quinones-Hinojosa hinted as much in a recent New York Times op-ed. “Our minority trainees are exhausted,” they said. “They are drained by the constant bombardment of narratives and stereotypes that compromise their ability to focus on their training. The prejudice is crushing their creativity and stifling their innovation. It is suffocating a generation of biomedical researchers.”