Candace raises a couple of interesting points.

First, sometimes it is true that a diligent student can’t take a course he needs because it isn’t being offered or all the sections are full, or for some other reason. But we’re talking about graduation rates within six years. I should think it very, very rare that a student who needs Course X to complete his major can’t get into it in his fifth year in school, much less his sixth. And how many schools are there that say to such a student, “You’ve been around for five years and have tried to get that last course you need to graduate, but because we didn’t offer it, you can’t have your degree.” Few schools, I think, have that sort of Post Office inflexibility.

Second, it’s unquestionably true that many lower-tier institutions admit students who have woeful academic abilities. But the schools usually have woefully low academic standards to match and bend over backwards to retain even the most disengaged and hapless students. Some of the students admitted at open admission schools manage to graduate; why not the others? Is it that they simply can’t handle even the watered-down coursework where it’s hard to get less than a C? Or is it not more often that they just don’t try?