Peer delinquency and student achievement in middle school

This paper studies the relationship between peer delinquency and student achievement in North Carolina middle schools. We define severity of the delinquent act using the associated punishment and calculate the average exposure to peer delinquency. Our identification strategy uses this new measure, a rich set of control variables including student, peer, and teacher characteristics, and a novel instrumental variable that captures the indirect social network impact of peer misbehavior. The instrument uses lagged delinquent behavior from students who went to 5th grade with peers of the index student's current 6th grade peers but not the index student him/herself. A 10 percent increase in the number of "major" incidents that a student at an average North Carolina school is exposed to was associated with a 6.2 percent of a standard deviation decrease in his or her standardized math score.