Can someone explain these college hireabilty rankings?

It's made up and almost completely useless. The fact that Georgia Tech went from #1 to #7 (I go to this college and know this numbers) shows that.

The idea I'm going with is that A GT is not worse of an employee than he/she was last year.

The idea is somewhat correct in having a ranking for the workforce cause most other rankings are research based - i.e. they look for how good a Phd you are, not how well you can work at a company as a non-research employee.

You have to also consider that recruiters are playing a numbers game. They need to look at universities with larger graduating classes to help improve their odds of hiring.

Do we need to explain? This site is obviously not a reputable source of any sort of information.