Normally, schools offer scholarships to entice students to enroll. This year, the Massachusetts Institute of Technology's business school handed them money to go away.

The Sloan School of Management's full-time M.B.A. program, usually about 400 students, was oversubscribed by an unusually high number of students this year. Rather than expand the class size, the school asked for volunteers willing to wait a year to enroll, sending out an e-mail just a couple of weeks before the Aug. 23 kickoff barbecue. By that point, many...