In the world of higher education, you will find few buildings less remarkable than the Delaware County Technical High School in Broomall, Pennsylvania.

But inside—along a single hallway—a little-known program ranks with the biggest names in higher education, and, in some cases, outperforms them. By one measure, it’s among the best deals in higher-ed right now—a mighty engine of value in an era where college debt is at the forefront of national politics and overburdened families question the worth of a degree.

As Democratic presidential candidates debate what to do about student loan debt, one low-cost, simple policy change could increase college graduation rates among lower- and middle-income students—and, in many cases, reduce their need to borrow. All students applying to college should fill out and submit the Free Application for Federal Student Aid, and every college should be required to report the incomes of all their students.

Catharine B. Hill, managing director of Ithaka S+R and president emerita of Vassar College, explains.