Students spend an average of $900 a year on textbooks—20 percent of tuition at an average university and half of tuition at a community college. Textbook prices have increased at four times the rate of inflation since 1994 and continue to rise.

Our research demonstrates that the rising costs of textbooks is not inevitable, and that policy solutions exist to make textbooks part of an affordable college education. Publishers produce new editions of textbooks every 3 and a half years—even in fields where information hasn’t changed significantly like math and chemistry. New editions prevent faculty and bookstores from using the old edition.

Publishers also “bundle” lots of extras with their textbooks—CD-ROMs and workbooks that drive up prices and make books harder to resell.

Professors and college administrations can do a lot to to rein in high prices, but Congress should require publishers to curb practices that drive up the cost of a college education.