Estimating the effect of friendship networks on educational outcomes and health behaviors of adolescents


Zhang, Yuxiu & Fletcher, Jason M. (2012). Estimating the effect of friendship networks on educational outcomes and health behaviors of adolescents. 2012 Add Health Users Conference. Bethesda, MD.


Researchers typically examine peer effects by defining the peer group broadly due to the lack of friendship information and to enable the use of plausibly exogenous variation in peer group composition across cohorts in the same school. To solve this common problem, this paper estimates a linear probability friendship formation model using the school sample of Add Health, and generates predicted values of friendship ties. Using these predicted values as instruments, we are able to identify the causal effect of the composition of nominated friends by maternal education and racial categories on students’ educational outcomes, evaluation of school environment and health behavior (such as smoking and drinking). We find, first, the impact of friendship formation differs for male and female students. For females, students who have more friends whose mothers graduated from college are more likely to have higher self-reported GPA. For males, the impact of friend group composition is mainly on drinking behavior. Boys with one or more friends whose mothers are college graduates are 2-4% less likely to drink regularly or get drunk regularly. Regarding racial composition, we find controlling for own maternal education and ethnic/racial group, students with a high share of minority among these friends are more likely to drink and get drunk regularly. No significant effect of friendship composition is found for smoking.


Reference Type

Conference proceeding

Book Title

2012 Add Health Users Conference


Zhang, Yuxiu
Fletcher, Jason M.

Year Published


City of Publication

Bethesda, MD

Reference ID