A recent paper illustrates the extent to which undermatching dims the prospects of already-disadvantaged students: Those who undermatch—who are predominantly low-income and students of color—are less likely to graduate within four years, as well as within six years, than their peers who did not. Chungseo Kang and Darlene Garcia Torres, both education-policy scholars at State University of New York at Buffalo, used longitudinal U.S. Education Department data to create a national sample of nearly 5,000 students who enrolled in four-year institutions within a year of high-school graduation.

The researchers found that undermatching was highest among black students, at 49 percent. And the phenomenon seemed to have the most acute effect on Hispanic students: After controlling for various characteristics, the six-year graduation rate for those who undermatched was 28 percentage points lower than it was for those who didn’t.

Minority and low-income students undermatch for countless reasons. They may not have been made aware of their college options, some because they didn’t have a guidance counselor to do so. Those who did learn about their options may have received the information after the application deadline. Then there’s the fact that college recruiters tend to look for students at high-achieving high schools. And sometimes students may feel—or have been told—that selective colleges, or college more generally, is simply out of their league. Or that those selective schools are cost-prohibitive—even though such institutions tend to be more generous with financial aid than less-selective ones.

Chingos admits that highly selective colleges enroll a miniscule portion of the higher-education population, and that policymakers and the media may give these institutions outsized attention. A study published in the Journal of Labor Economics last year highlighted the importance of increasing access to public, 4-year colleges, a practice that substantially increases degree-completion rates. However, it is clear that many highly selective institutions could be doing more to socioeconomically diversify their student bodies, and that the benefits of attending them could have a profound impact on the leadership pipeline. Still, a 2016 Jack Kent Cooke Foundation report found that selective colleges had since 2000 hardly increased the number of students who receive Pell grants, which are reserved for low-income students.

There’s no doubt that undermatching occurs—but solutions to the problem are far less clear. One idea that has bounced around, including in the Cooke Foundation report, is for college-admissions offices to give extra weight to the applications of low-income students—a “poverty preference,” as the foundation called it. Colleges already give preference to other hopefuls, including recruited athletes and, perhaps most infamously, students whose relatives are alumni. So, the logic goes, why not do the same for low-income applicants?