Over the last 17 years, Vincent Tinto’s 1994 book, “Leaving College: Rethinking the Causes and Cures of Student Attrition,” has been a standard read for those studying student retention. But now Tinto has authored a sequel, “Completing College: Rethinking Institutional Action,” with a sobering message for college administrators: College may be available to more people than ever before, but the graduation rate is not improving significantly — and, in some cases, it’s actually declining.

“While the gap between high- and low-income students, in terms of going to college, has decreased, the gap in college completion between high and low income has actually increased,” explains Tinto, a professor at Syracuse University. “So something’s amiss. The sum set of my experience is telling me the following: While colleges have instituted a range of retention programs, for the most part those programs have sat outside the classroom. They’re disconnected.”

In the new book, Tinto calls for a reinvestment in the undergraduate classroom. That may sound logical enough, but he also highlights institutional forces working against an undergrad-learning-first institutional approach. “For low-income students, most of them work outside the college and often commute. The only time they’re on campus is when they’re going to the classroom,” explains Tinto. “If we don’t make success in the classroom the centerpiece of our work, we’ve missed the whole point of it.”