Updating a previous systematic review of the literature, this review summarizes the literature over the last 5 years on the relationship between school-based extracurricular activity participation and academic achievement, substance use, sexual activity, psychological adjustment, and delinquency. The review also considers mediators and moderators…

Matching methods such as nearest neighbor propensity score matching are increasingly popular techniques for controlling confounding in nonexperimental studies. However, simple k:1 matching methods, which select k well-matched comparison individuals for each treated individual, are sometimes criticized for being overly restrictive and discarding…