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<p>Which are you asking about? The usual 4- 5-, and 6- year graduation rates that institutions report? </p>
<p>That graduation rate tells you a few things. How happy students tend to be with their choice of institution, whether they tend to make it through in a timely fashion, and so on. You don’t always know the reasons behind them though. For example, are people not graduating on time because they stop out to work (which might reflect on financial aid, or it might reflect on socioeconomic background, or both)? Or are they unable to get required classes? The higher the graduation rate, the more certain one can be that students like their choice, that the school facilitates progress towards degree, that students tend to be goal-oriented when it comes to the degree. </p>
<p>If you’re asking about the other graduation rate “performance” measure. The over or under thing is based on the expected graduation rate. I thought it was based on a model which takes more factors in account, but interesteddad indicated it’s actually based on only two variables, SAT and per-student spending. It is supposed to tell you about the “value-added” qualities of the school (I talked about this on page 1). That is, how much better does the institution do with its students given what we’d naturally expect of students of their calibre on any campus? This measure may be telling for some schools but may not be very meaningful for schools at the top end of the spectrum who essentially have nowhere to go but down.</p>