“As access increases, stratification increases at the same time,” Anthony Carnevale, director of the center, said at the initiative’s unveiling earlier this month.

Nicole Smith, the center’s chief economist, noted that much of that stratification has to do with the cost of attending college and a lack of resources among first-generation students, who are disproportionately likely to be students of color. Harder-to-measure factors like culture shock and stereotypes can also make completing college a challenge.

The Education Trust found that graduation gaps have narrowed by less than one percentage point in 10 years—meaning, at the current pace, the gap will not be closed in this century. The gap in graduation rates between white and black students has actually grown.

“We caution institutional leaders who celebrate their graduation rate gains to take a good look at their data and ask whether they are doing enough to get more African American, Latino, and Native students to graduation and to close completion gaps,” Kimberlee Eberle-Sudré, The Education Trust’s higher education policy analyst and coauthor of the report, said in a statement. “The answer for many institutions is, ‘No.’ Fewer than half of the institutions we analyzed raised rates for their underrepresented students and cut gaps. Institutions can and must do more to serve underrepresented minority students.”

So what could be done to speed up the process and broaden its scope? It’s an important question that comes as the Supreme Court again this week prepares to hear a challenge to affirmative action, in a case that could have far-reaching implications when it comes to the number of black and Latino students who are admitted to selective schools.

The report highlights 26 schools that are both raising graduation rates across the board and closing gaps, and their strategies. San Diego State University urges students who need remedial courses to take them the summer before their first fall semester, so they don’t begin their college careers already behind. North Carolina State University fosters peer mentoring. Broadly, the report argues, increasing graduation rates for underrepresented students will require deliberate action by schools—it's not just going to happen on its own.

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Emily DeRuy is a former staff writer at The Atlantic, where she covered education. Connect Twitter