The pricing and advertising of tied add-ons and overages have come under increasing scrutiny. Working with a large Turkish bank to test SMS direct marketing promotions to 108,000 existing holders of "free" checking accounts, we find that promoting a large discount on the 60% APR charged for...

If students tend to choose instructors with high teaching ability, a negative link between class size and student performance may remain obscured until this kind of sorting has been taken into account. Using data from student evaluation surveys, we confirm that it is crucial to control for...