[starkness]

Sure, but a lot of the people taking classes at the Extension School don't want a degree. For example, I had students whose employers were paying for them to take a single course to give them some background knowledge or insight into their jobs. They're not looking to graduate; just to take a class or two that will help them with their careers.

[slg]

That is a good point and the numbers aren't measuring the exact same thing (on the flip side of your example is the number of applicants to Harvard College who might not attend even if accepted). I didn't intend to reference them as some justification that the two schools are in any way equal. The only reason to really compare the two rates is because they have similar values and highlight the differences between the two schools. The toughest part of the College is getting in, the toughest part of the Extension School is getting out.