Two new studies offer emphati nd 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, being presented Monday 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.

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.

“These kids, even though they have pursued the American dream, they’re starting their careers with hugely unequal amounts of student loan debt,” Houle said. “That could be the difference of a kid who can take an unpaid internship that would put their career on an upward trajectory.”

The caveat with Houle’s study is that he looked only at people who attended some college.

As Houle acknowledges, while those from low-income families who go to college may get out of school with less debt, poorer students are still less likely to go in the first place. If the Georgetown survey shows anything, it’s that graduating with a moderate amount of student debt is still much better than not graduating.

So the lesson isn’t necessarily that the lowest-income students are better off overall: Just 8 percent of those from families in the bottom income quartile (under about $36,000) have earned a bachelor’s degree by age 24, compared to more than 82 percent from the top quartile (roughly $108,000).

But Houle’s study does illustrate the serious bind of families above the very bottom (earning between roughly $36,000 and $65,000). Just 17 percent of those students earn a degree by 24, and they’re racking up more debt in the process.