GMAT scores correlated to MBA grades.
I found this obscure research report that was instituted by at least one major MBA program to guide acceptance using gmat scores and a math formula.
The major point of this gmat score research information is that a student's performance on the gmat was shown to predict, to some extent, their likelihood of success in the core MBA classes.
How GMAT scores matter.
Researchers in a top MBA program attempted to come up with a more objective way to sift through the thousands of mba applications received every year. They tried to measure the predictive value of multiple factors including work experience, personal essays, recommendations, and applicants' average gmat scores using a math technique called linear regression.
Does it work? YES! Did they institute it? YES!
Read more about the formula on the next page...