Shortly before ten o’clock on a recent warm summer morning, the grand old Apollo Theater on Harlem’s 125th Street filled up with the friends and families of the members of Democracy Prep Charter High School’s third-ever graduating class. The soon-to-be graduates milled about in the lobby, hugging each other and taking selfies in their bright golden robes and mortarboards before filing in, grinning, for their moment of glory.

I got to know each of these sixty-one students in my senior seminar class this year. It was a deeply satisfying year for the school and an extraordinary one for the students, each of Latino and African descent, and nearly all of modest means. Come September, every single one of them will attending colleges, including several institutions that would be the envy of parents and students at the elite private schools just a few blocks south of here. Ashlynn and Chris will be heading to Dartmouth; Hawa turned down Stanford to attend Yale; Tyisha will join the freshman class at Princeton. Other members of Democracy Prep’s Class of 2019 are bound for Emory, Smith, SUNY Albany, Boston College, and Brown, among many others.

Class of 2019 is not a typo. It has become nearly de rigueur for high-performing, “no-excuses” charter schools to add four years to the graduation date for each departing class. It marks the year departing scholars are scheduled to graduate from college, an endearing aspirational quirk and one last dose of high expectations before commencement. But there’s an uncomfortable truth that must be acknowledged even as we celebrate. At present, the odds are still against most low-income kids of color reappearing at another graduation ceremony four years hence. Or ever.

A sobering recent report from the National Center for Education Statistics shows just how long the odds are, even for those with college aspirations. Starting in 2002, researchers began tracking fifteen thousand U.S. high school sophomores from across the socioeconomic spectrum. At that time, roughly 70 percent of those tenth graders planned to go to college. That ranged from a high of 87 percent among students whose parents had the highest level of income and education to 58 percent of those whose parents were the least educated, poorest, and largely unskilled. Among this latter group of students, a mere 14 percent of the total—and only one in four of those who planned to as sophomores—had earned a college degree by 2014.

Many of us have aspirations that exceed our abilities. Thus, the most obvious explanation for this disparity would be that low-income children were unprepared or overconfident, or else lacked what it takes to succeed in college. But the study showed otherwise. Writing in the New York Times, Susan Dynarski, a professor of education, public policy, and economics at the University of Michigan, notes that each student in the study took math and reading tests. Nearly three out of four of the highest-scoring students from the most affluent families completed a college degree as of 2014. But for low-income kids with the same achievement level, the college completion rate was only 41 percent. Even more telling: “A poor teenager with top scores and a rich teenager with mediocre scores are equally likely to graduate with a bachelor’s degree. In both groups, 41 percent receive a degree by their late twenties,” Dynarski observed. The American Enterprise Institute’s Andrew P. Kelly made a similar point in a paper last year for Fordham’s “Education for Upward Mobility” conference.

The report adds cold, hard data to what has long been known among education reformers and the high-achieving charter schools they champion: Getting low-income “first-generation” kids into college is hard. Getting them to graduate from college is harder.

For years, pioneering charter school networks like KIPP, YES Prep, and others won legions of admirers by ensuring that nearly every student they graduated went to college, usually the first in their families to do so. A 2011 report from KIPP itself, however, found that only 33 percent of their earliest cohorts of students had actually earned a college degree. On the one hand, that’s roughly four times higher than the rate for disadvantaged students as a whole. But it was far below KIPP’s own internal goals and a wake-up call for a reform movement that had long campaigned for college as an essential path to upward mobility.

Since then, KIPP and others have become increasingly focused on “college match.” This typically means partnering with colleges like Franklin & Marshall and Spellman College—which tend to feature high graduation rates both overall and for low-income students, generous financial aid, and diverse social environments—to make it more likely for “first-generation” kids to persist and succeed.

Perhaps even more critically, we are learning that maintaining close ties to alumni matters a lot. “Once in college, students submit course selections, financial aid documents, and most importantly, college transcripts to us so that we can academically advise and proactively address any issues that may come up,” says Jane Martínez Dowling, executive director of KIPP NYC Through College. For middle-class and affluent children, this kind of constant monitoring, advising, and problem-solving tends to be baked into their lives, whether through aggressive helicopter parenting or simply having friends and family members who’ve been to college and are neither awed by the process nor intimidated by pitfalls. My now-former students will benefit from this kind of post-graduation counseling—Democracy Prep, like KIPP and many others, keeps close tabs on alumni. So far, nearly nine out of ten remain enrolled—an encouraging figure, albeit from a cohort of fewer than 100 students.

The senior speaker that day, Fordham-bound Briana Mitchell, took justifiable pride in the accomplishment of her classmates, who have already beaten the odds simply by graduating and winning acceptance to college. “Who would have thought that these students are going to some of the top colleges and universities around the world?” she said, to enthusiastic shouts and applause. “Who would have thought that this could happen when all odds were against us?”

Graduation day is a time for celebration and excitement, not for doubts. But there can be no doubt that the hard work is not over for these kids. In many ways, it’s just begun.

Editor’s note: This post originally appeared in a slightly different form at U.S. News & World Report.