Kim A. Wilcox, chancellor of University of California Riverside, writes: In the next several weeks, millions of high school seniors will apply to colleges and universities across the nation. If you are one of them — and if you come from a low-income family or are a minority student — I urge you not to look at higher education rankings systems that emphasize reputation, acceptance rates and alumni giving.  Instead, keep your eye on rankings that rely upon a different set of numbers: Namely, graduation and retention rates. That’s because the current trends in enrolling and graduating low-income and minority students threaten social justice in higher education.