An anecdote supporting the education-as-signaling model
When I was starting at the University of Chicago, back in 1999, one of the career-counseling people said something I’ve never forgotten: "We could put you guys on a cruise ship for the next two years, and you’d still get the same jobs."
She was stating, in a rather funny way, something almost everyone knows: Most of the economic value of an MBA from an elite business school comes from demonstrating that you can get into an elite business school. The rest comes from the classmates you meet, networking and project experience you get. Something close to zero percent of the value comes from your classwork.