Still, there is another variable needed to answer the question, “Is college worth it?” That’s the cost of college, and that has been rising rapidly.

On average, the answer is pretty clear: A degree is worth it, to the tune of $1.3 million in additional lifetime earnings, a very good return on even an expensive degree.

But, as Georgetown’s Anthony Carnevale acknowledges, there’s no such thing as a generic bachelor’s degree. Where you study, and what you study, matter a lot.

“What people shouldn’t take away from this is you can get any old BA or AA,” Carnevale said. “They need to get past that. They need to think about which degree and what it will it do for them.”

As many as one in five undergraduate degrees — for instance in counseling, at least for those who don’t go on to get a master’s — produce average earnings no greater than those of a high school graduate. Many types of AA degrees produce better average earnings than some bachelors. The research paints a powerful portrait of an economy where more education is better, but the kind of education matters too.

The second study, presented Aug. 20 at the American Sociological Association’s annual meeting in Denver, highlights the particular burden of growing student debt on middle-class families, who may be too well off to qualify for financial aid like Pell Grants that target students from the poorest families.

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In the study, University of Wisconsin demographer Jason Houle finds students from middle-income families rack up more student loan debt on average than others: not only students from high-income families — no surprise — but also than those from low-income families.

About 40 percent of students left school with debt, and the average was about $22,000. But students from families earning between $40,000 and $59,000 were saddled with $6,000 more on average than peers from families earning less than $40,000. Students from the next tier — family income between $60,000 and $99,000 — had $4,000 more in debt than their lowest-income peers.

One reason is that federal grant aid targets the lowest-income students — roughly 90 percent who receive Pell Grants come from families earning under $50,000. Lower-income students may be also be more debt-averse, causing those who go to college to choose cheaper schools.

But the figures reinforce the struggles of families just above the bottom level to afford even the average public 4-year college, with tuition plus room and board (before factoring in financial aid) now running more than $17,000 per year.

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