And here's the key bit: Many colleges, he argues, appear to be playing an "elaborate shell game," relying on federal grants to cover the costs of needy students while using their own resources to furnish aid to richer undergrads.

"With their relentless pursuit of prestige and revenue," Burd writes, "the nation's public and private four-year colleges and universities are in danger of shutting down what has long been a pathway to the middle class for low-income and working-class students."

Give to the Rich, Overcharge the Poor

Burd's paper isn't an indictment of the entire higher ed establishment -- just a startlingly large portion of it. Many of the worst offenders he identifies are small, private colleges with meager financial resources, or public schools concentrated in a handful of states like Ohio, Pennsylvania, and South Carolina that have moved to what's called a "high tuition, high aid," model. The theory was that, in a time of tight state budgets, charging wealthy students exorbitantly would allow them to charge poorer students reasonably.

It hasn't worked out that way. Unlike twenty years ago, Burd explains, it is now more common for colleges to hand out aid packages based on "merit" rather than financial need. And "merit" is often a rather nebulous concept.

Sometimes, colleges (and states) really are just competing to outbid each other on star students. But there are also economic incentives at play, particularly for small, endowment-poor institutions. "After all," Burd writes, "it's more profitable for schools to provide four scholarships of $5,000 each to induce affluent students who will be able to pay the balance than it is to provide a single $20,000 grant to one low-income student." The study notes that, according to the Department of Education's most recent study, 19 percent of undergrads at four-year colleges received merit aid despite scoring under 700 on the SAT. Their only merit, in some cases, might well have been mom and dad's bank account.

There's nothing inherently wrong with handing out tuition breaks to the middle class, or even the rich. The problem is that it seems to be happening at the expense of the poor. At 89 percent of the 479 private colleges Burd examined, students from families earning less than $30,000 a year were charged an average "net price" of more than $10,000 annually -- "net price" being the full annual cost of attendance minus all institutional and government aid. Less technically, it's what students can actually expect to pay. At 60 percent of private colleges, that net price was more than $15,000.

In other words, low-income families are routinely being asked to fork over more than half of their annual income for the privilege of sending their child off to campus for a year.

Feeding Off the Government

Many these institutions didn't just soak poor students; they also enrolled them in droves, collecting taxpayer dollars in the process. Burd identified 287 private colleges where more than a quarter of the student body received federal Pell Grants, which go to undergrads from low-income and working class families. These schools charged families earning under $30,000 a median net price, again, of more than $15,000.