>That said, a study that includes post-bachelor degrees in the ranking would be interesting. What would be especially informative would be a combined ranking that factors the average cost of education in with the average earnings increase/decrease.

Yeah, I think the most useful comparison would be to make comparisons based on the average return for the most typical terminal degree in your field would be, or at least to give you a suite of responses based on varying degrees.

>Perhaps a masters in psychology still gets you less than a BS in mathematics, perhaps not, but it would be neat to see.

As a side note, is a BS in pure math particularly useful, beyond the fact that it's a bachelor's degree? That always struck me as one of those disciplines that would require an advanced degree to be of use. (My freshman year calculus TA, when asked by one of his students if he was going for a master's, said, "No, I'm a PHD student. The master's degree is the door prize of mathematics.")