Teachers often deliver the same lesson multiple times in one day. In contrast to year-to-year teaching experience, it is unclear how this teaching repetition affects student outcomes. We examine the effects of teaching repetition in a setting where students are randomly assigned to a university...

We randomly assign more than 6,000 students from 150 primary schools in Bangladesh to work on math assignments in one of three settings: individually, in groups with random schoolmates, or in groups with friends. The groups consist of four people and are balanced by average cognitive ability and...