<p>rogracer-
What do you mean when you say that some MIT students were truly incompetent? Socially incompetent? I find it hard to believe that any MIT students are incompetence although some may have underperformed relative to their ability. </p>
<p>Furthermore, we are not trying to predict the behavior of individual students directly. We are predicting the “behavior” of freshman classes as a whole. There is a difference.</p>
<p>When the correlation is +.8 it means that about 64% (.8 squared) of the explanation can be attributed to SAT scores. There is still variability among schools with very similar SAT scores. (This is the “residual” that noimagination analyzed. Which schools do best with the students they have?)</p>