This should be fairly obvious; I think you have to do some work to believe it's possible that it isn't true. How can you measure how well a university prepared a student if you don't even know what the student majored in?
On thing you can measure some fairly rudimentary stuff they should have had coming in (grammar, basic math, etc.). But this is answering the wrong question; universities shouldn't be responsible for catching students up. It's a disservice to people who actually wanted to take the course in which the review happens.
The other thing you can do is measure generic "critical thinking". But I think this sort of test is ripe for abuse. I don't trust college administrators to not abuse it. And besides, generic "critical thinking" isn't. See the link I posted in my other response here.
I don't know of a good answer, but I think with all the money that gets thrown at schools, it's worth asking how they are improving the students.
I see this in NYC. The mayor's belief is that we are doing a little too much testing, and closing too many schools. Their reaction to bad schools is "We just might not be measuring the learning." In this case, they seem to be doing an accurate job of measuring the bullying at least.