Joe Posnaski - an outstanding on-line baseball writer, one of the very best - has an interesting column where he riffs off of a Nomar Garciaparra quote:
There's no stat yet that measures heart.
Just as Joe riffed on Garciaparra, I'd like to riff a bit on Joe's blog. I think he offers a wonderful (if likely unintentional) metaphor for a student's GRE scores and their GPA.