Richard Vedder writes,

approximately 60 percent of the increase in the number of college graduates from 1992 to 2008 worked in jobs that the BLS considers relatively low skilled–occupations where many participants have only high school diplomas and often even less.

This reinforces my suspicion that if one does the calculation at the relevant margin, adding to the pool of college graduates will not raise productivity or wages.

I hasten to add that this is a highly controversial issue. For some people, the best hope for reducing the dreaded Rising Inequality is more education. Of course, for some people (not necessarily the same people), the best hope for ____ is renewable energy, where the blank can be filled by fighting terrorism, saving the climate, or what have you. These are the sorts of issues where my Sowellian constrained vision makes me unpopular among those with the unconstrained vision.