Peer effects and selection effects on smoking among Canadian youth

A number of studies have indicated that peer smoking is a highly influential factor in a young person's decision to smoke. However, this finding is suspect, because the studies often fail to account for selection and simultaneity bias. This paper develops an econometric model of youth smoking that incorporates both peer effects and selection effects. Identification is achieved by using the degree of selection on observables as a proxy for the degree of selection on unobservables. The results indicate that peers have some influence on a young person's decision to smoke, but that influence is much weaker than is suggested by reduced form models.