Stuck, that is, until they started looking at what was happening with students’ GPAs. Despite the aforementioned trends among the college-going population, students were, on average, earning higher grades in their first year of college. “[GPAs are] going up, and as best we can tell, there’s not a good reason that they’re going up, in terms of student behavior or preparation or anything like that,” Denning said.

If grades are improving but there’s no reason to think that students have become better students, an interesting possibility is raised: The unassuming, academic way Denning puts it in a recent paper (co-authored with his BYU colleague Eric Eide and Merrill Warnick, an incoming Stanford doctoral student) is that “standards for degree receipt” may have changed. A less measured way of saying what that implies: College may have gotten easier.

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Christina Ciocca Eller, a sociologist at Harvard who studies higher education, and who wasn’t involved with Denning’s research, points out that “easier” could mean a couple of different things. College could have gotten easier in the sense that it presents students with simpler material than before, or in the sense that it presents students with similar material as in the past but grades them more forgivingly. “I actually think that the latter explanation, about grade inflation, is more plausible,” Ciocca Eller told me, though she also noted that the college-has-gotten-easier hypothesis is not definitive.

Denning himself noted this, too. He called the paper, which hasn’t yet been published in a peer-reviewed academic journal, “a first stab”—an exploration of a question he welcomes other researchers to look into. It could well be the case, he said, that “schools are just better at helping students” than they used to be. Indeed, many colleges have launched initiatives to help more students graduate, but the effectiveness of these programs varies, and Denning said he does not have specific-enough data to analyze their role in rising graduation rates nationwide.

Whatever is responsible for the increase, it seems to serve the needs of colleges and universities, especially public ones. Lately, Ciocca Eller said, schools are being held more accountable for their graduation rates, with some states tying educational funding to certain statistical benchmarks. “Potentially, there’s pressure on faculty to help students, especially underprepared students, to move them through the curriculum in order to keep churning up the graduation rate,” she said.

Denning and his co-authors acknowledged this possibility, noting in their paper that altering what’s necessary to get a degree is “the lowest cost way to increase graduation rates.” But colleges’ widespread use of this tactic, conscious or not, is at this point just guessed at and far from proven.