Enrollment is down for the first time in memory, and critics complain college is too expensive, too elitist, and too politicized. The economist Chris Paxson — who happens to be the president of Brown University — does not agree. (Part 3 of “Freakonomics Radio Goes Back to School.”)

We think of them as intellectual enclaves and the surest route to a better life. But U.S. colleges also operate like firms, trying to differentiate their products to win market share and prestige points. In the first episode of a special series, we ask what our chaotic system gets right — and wrong. (Part 1 of “Freakonomics Radio Goes Back to School.”)