Now, the "price" is higher (which is used to create the graphs in the linked article), but the effective cost for the student hasn't increased quite as proportionally because he has a government voucher to use.
Greatly oversimplified, I know. We understand what someone means when he talks about the average price of a gallon of gas at a gas station, but we don't have a common definition for the "price" of education. Out of pocket not counting grants/scholarships? Do we discount the cost if the loans are at a below-market rate because of government guarantees?
Heck, even the gallon of gas "price" is hard to define. Marathon gives me back 5% on gas purchased with my Marathon card. What's my average price per gallon?
Come to think of it, I've never personally seen a graph of tuition inflation with out-of-pocket payment, private loan payment, and federal aid payment all on top of each other, mapped over time. THAT would be a telling graph.