U.S. Secretary of Education Arne Duncan says schools not on track to graduate at least half of their basketball players should not be allowed to compete in the NCAA tournament.

Duncan proposes bans for teams with a score lower than 925, which predicts a graduation rate of roughly 50% of a team's players.

"The math on this is not complicated," Duncan said. "If you can't graduate one in two of your student-athletes, I just question the institutional commitment to academics. And I think if the NCAA were to draw a line in the sand, you'd see this behavior change very rapidly."

Duncan cites an analysis by the Knight Commission on Intercollegiate Athletics, out Thursday, that says 43.7% of the revenue paid to conferences from the men's tournament the last five years was earned by teams not on track to graduate half of their players.