[Found here.]There is one school of thought that holds that the reason why people with college degrees earn, on average, quite a bit more than those who don’t have them is that college does a lot to augment their “human capital,” giving them the skills and knowledge to go forth into the world and accomplish great things that the poor slobs with mere high school diplomas never could. A rival school of though holds that college really doesn’t do much at all to augment one’s human capital (with some exceptions, such as engineering degrees), but merely acts as a screening device that enables employers to figure out who’s most apt to be trainable and reliable.
The former school produces blathery studies lamenting that we aren’t graduating enough people from college and calling for more subsidies.
The latter school occasionally produces a hard-bitten expose of the college degree mania — such as this one written by Gary North and available here.