Investments in out-of-school-time programs have increased dramatically in recent years. In this paper we ask whether participation in out-of-school extracurricular activities improves academic achievement or behavior for elementary school children. Initial analyses were conducted using relatively standard techniques to control for the fact that students who participate in out-of-school-time extracurricular activities differ in important ways from nonparticipants. These analyses found statistically significant and positive effects of participation in arts, music, drama, and language classes. However, the initial positive effects disappeared when more appropriate analytical models were used.