The Consequences of Friendships: Evidence on the Effect of Social Relationships in School on Academic Achievement

This paper examines the impact of youth friendship links on student’s own academic performance (grade point average) using the Add Health. We estimate a reduced form, high dimensional fixed effects model of within cohort or grade friendship links, and use this model to predict each student’s number of friends whose mothers have a four year college degree. The effects of friendship links are identified using across-cohort, within school variation in demographic composition of the student’s cohort or grade. We find that increases in number of friendship links with students whose mothers are college educated raises grade point average among girls, but not among boys. Additional analyses suggest a positive view of the school environment and a perception of one’s self as functioning well in that environment as possible mechanisms. The effects are relatively broad based across students over maternal education, racial and ethnic composition and across schools that vary in demographic composition over the same variables.