UNC President Erskine Bowles has made it clear that one aggressive priority of his tenure is increasing the retention rate in the system's campuses.

It is a move we have welcomed. For too long, and perhaps less worrisomely in a different era, many universities figured their job was to sign up qualified students -- and then set them free in a sort of sink-or-swim atmosphere.

If you're good enough to be on our campus, the thinking seemed to go, you're good enough to do the work. And if not -- well, it's up to you to figure it out. Some in higher education even took a steady attrition of students flunking out or abandoning their studies as just part of the cost of doing business, perhaps even a perverse badge of honor. We're tough here, and only the strong survive.

Well, that theory, if it ever worked, isn't right today, and few colleges and universities -- certainly not those in the UNC system -- consciously follow anything like that model. Still, at many campuses, too many students enter poorly prepared, whether for the academic work itself or for the transition to a college environment much different than the high school they left behind.

So Bowles has been right to press leaders of his campuses to address that issue seriously, and to expect higher percentages of students who walk in the door to walk the graduation stage four, or at least five, years later with a diploma.

This week, N. C. Central University's chancellor, Charlie Nelms, raised a bit of a caution flag on that drive. He wants to be sure Bowles and other top system administrators acknowledge that schools like NCCU have a different mission, and a different challenge, than campuses such as Chapel Hill, N. C. State University or UNC Wilmington.

Noting to his board of trustees that NCCU is a "low-wealth school" where nearly all students receive financial aid and many come from difficult backgrounds, Nelms warned against a "one-size-fits all solution."

We see some merit in Nelms point, but hope that his take isn't a defensive undercutting of standards that ultimately victimizes students with the perverse burden of lowered expectations.

Nelms himself has raised concerns about his university's low retention rate, and told The Herald-Sun's editorial board earlier this year that raising it was a high priority. So we know full well his heart and head are in the same place as Bowles' -- and we suspect Bowles understands the point Nelms is carefully making.

The challenge they and their colleagues face is striking the right balance between aggressive standards and still assuring schools such as NCCU remain beacons of opportunity for some students who otherwise might have little.