Students play with a Frisbee at the University of Maryland in College Park.
(Sarah L. Voisin/The Washington Post)

In an op-ed in the New York Times over the weekend, University of Colorado law professor Paul F. Campos offered a provocative answer to the frequently asked question: why is college so expensive these days?

Campos says it's because colleges are expanding their administrative staff and paying them big salaries, which drives up costs for families. And he argues that this is happening even though state spending on higher education has actually skyrocketed.

Some of this is true, but it's a bit more nuanced than the article suggests.

He writes: "Public investment in higher education in America is vastly larger today, in inflation-adjusted dollars, than it was during the golden age of public funding in the 1960s...In other words, far from being caused by funding cuts, the astonishing rise in college tuition correlates closely with a huge increase in public subsidies for higher education."

Indeed, states have increased their higher education budgets since the 1960s because of the explosive growth of the number of students enrolled in college. But the amount of money states spend on each of those students has been in flux for decades and sharply fell during the 2008 economic recession. Legislatures responded to dwindling tax revenue at the time by slashing higher education funding by 23 percent per student, according to the Center on Budget and Policy Priorities, a think tank.

"You really have to look at what states are providing per student to make sure there is enough money to serve the increasing number of students," said Donna Desrochers, principal researcher for the Delta Cost Project at the American Institutes for Research.

[Going to a public college isn’t as affordable as it used to be]

Campos concedes in his piece that "total state appropriations per student are somewhat lower than they were at their peak in 1990." But that's an understatement considering that per-student spending has fallen nearly 30 percent in the past 25 years, said Mark Huelsman, a policy analyst at liberal think tank Demos.

"That’s not really 'somewhat lower.' And total educational revenue – tuition plus state support, basically – hasn’t really budged all that much," he said. "If higher education is a public priority, increased demand would lead to investment that keeps pace with that demand. It’s a policy choice to not do that, or more specifically, to seek lower tax revenues at the expense of funding public higher education."

What's really telling is how much of the cost of college is covered by the state versus by families. Researchers at the Government Accountability Office found that the money public universities collect in tuition surpassed the money they receive from state funding by 2012.

Tuition accounted for 25 percent of school revenue by then, up from 17 percent in 2003. During that time, state funding fell from 32 percent to 23 percent. That's a huge difference from the 1970s, when state legislatures supplied public colleges with nearly 75 percent of their funding, according to the Federal Reserve Bank of Cleveland.

As state subsidies suffered during the recession, the federal government kicked in more money through programs like the Pell Grant, which awards money that does not have to be repaid to students whose household incomes are typically $60,000 or less. But that program has failed to keep pace with the cost of tuition. The maximum Pell award covered 77 percent of the cost of attending a four-year public university in 1980, but that fell to 36 percent by 2011, according to the Education Trust.

[House Republicans want to cut back grants for poor college students]

To be sure, many states are raising their investments in higher education coming out of the recession. Forty-two states have increased funding per student by an average $449 in the last year. Still, the average state is spending $2,026 less per student than before the recession, according to the budget think tank.

For Campos, it's not just a question of whether states are funding public colleges, but how those colleges are spending their money. And where they're spending their money, he says, is on hiring staff whose over-sized salaries are driving up costs.

It's true that there are more people in non-teaching positions than before. The number of professional staff--the IT guys, the folks in the diversity or admissions office--has grown by 60 percent between 1993 and 2009, according to the Education Department. These jobs tend to pay more than secretarial positions that once defined the administrative staff. Still, the increase in professional staff has balanced out the decline in administrative staff at many schools, said Sandy Baum, a senior fellow at the nonprofit Urban Institute.

"You can't just have people in the classroom, you have to have people providing student support services or students don't succeed," she said. "Of course there is duplication; of course we could increase efficiency...but at public institutions you don't have rapidly rising cost per student. That doesn't mean you can't keep costs down, but it is not the explanation for why prices are rising."

Want to learn more about the cost of college? Check out these stories:

The University of California just jacked up its tuition. Why your state could be next.

Middle-class families are fed up with their financial aid options

Students now pay more of their public university tuition than state governments