| Abstract: |
This paper estimates the effects of friends’ health behaviors, smoking and
drinking, on own health behaviors for adolescents while controlling for the
effects of correlated unobservables between those friends. Specifically, the
effect of friends’ health behaviors is identified by comparing similar
individuals who have the same friendship opportunities because they attend the
same school and make similar friendship choices, under the assumption that the
friendship choice reveals information about an individual’s unobservables. We
combine this identification strategy with a cross-cohort, within school design
so that the model is identified based on across grade differences in the
clustering of health behaviors within specific friendship patterns. Finally,
we use the estimated information on correlated unobservables to examine
longitudinal data on the on-set of health behaviors, where the opportunity for
reverse causality should be minimal. Our estimates for both behavior and
on-set are very robust to bias from correlated unobservables. |