Although the details are not evident from this short article, the idea seems to be that the grades a law student makes in school are more important than the school attended in determining career success. I mention this because I have seen first hand hiring committee's turn their noses up at a top ten grad from, say, Minnesota, in favor of a bottom of the top third or even lower -- much lower- Harvard grad. There is no way to put it other than it is an empirically unsound way to make the hiring decision. Why do they do that. Not to bore you for the 10th time, but for the most part the committees are composed of elitists and the hiring is self-referential -- they are hiring themselves or what they wannabe. So each year another batch of elite grads roles into a profession that has grown terribly stale and humorless. Plus, they are not that well educated. In fact, when I consider the interests of, let's say, an Exeter, Princeton, Harvard grad (the most elitist combo I can think of right now) I wonder what is going in in the classroom.
Could we test this. Not really. A few years ago I compared publications by elitist school grads with those of non elite schools. The problem was that once you get out of the second tier of Law Schools you are hard pressed to find any non elite grads to make the study meaningful.
Really, I think Harvard and Yale could start producing the Yugo car and half the law professors in the US would salivate to have one (especially if it came with a Harvard vanity plate). Why do I believe that? Because they already produce Yugo grads and the profs salivate.