This week I am reading a bunch of papers to get inspiration for a third year paper topic. This is from "Why Fighting Poverty is Hard" by Abhijit Banerjee of MIT:
"One way to distinguish the models of productive education from the signaling and distortion hypotheses about micro and macro returns is that the usual model is the MIT “engineering” metaphor in which education is subsequently used in innovation. The signaling model can be thought of as the “Harvard MBA” metaphor of education in which nothing is really learned but wages are higher because a highly ambitious group is pre-selected for employers. The “Harvard Law” metaphor is that in which wages are higher because real, privately valuable, skills are really learned, but these skills are of dubious social product."
Also check out this reason magazine interview.