Tyler Cowen considers the question of ‘pedigree bias’ in economics and other fields; while he follows up with an article that suggests pedigree bias may not be as pronounced as he initially suspected, nonetheless there is a clear relationship. I would imagine the relationship found in the Klein article would be even stronger if it measured initial hiring decisions, though.
My thoughts on such matter, at least as they pertain to political science, have been blogged previously and repeatedly, so I won’t belabor those points here.