I recommend skipping section 2, as it's long and a bit slow. Section 3 is the heart of the matter and here's an excerpt from that section:
To assess the effect of the Ivies, it makes more sense to compare the student who got into a top school with the student who got into that same school but chose to go to a less selective one. Three years ago, the economists Alan Krueger and Stacy Dale published just such a study. And they found that when you compare apples and apples the income bonus from selective schools disappears.
"As a hypothetical example, take the University of Pennsylvania and Penn State, which are two schools a lot of students choose between," Krueger said. "One is Ivy, one is a state school. Penn is much more highly selective. If you compare the students who go to those two schools, the ones who go to Penn have higher incomes. But let's look at those who got into both types of schools, some of whom chose Penn and some of whom chose Penn State. Within that set it doesn't seem to matter whether you go to the more selective school. Now, you would think that the more ambitious student is the one who would choose to go to Penn, and the ones choosing to go to Penn State might be a little less confident in their abilities or have a little lower family income, and both of those factors would point to people doing worse later on. But they don't."