Peer influence and selection effects on adolescent smoking

Background: Studies showing that adolescents are more likely to smoke if they have friends who smoke typically infer that this is the result of peer influence. However, it may also be due to adolescents choosing friends who have smoking behaviors similar to their own (i.e., selection). One of the most influential studies of influence and selection effects on smoking concluded that these processes contribute about equally to peer group homogeneity in adolescent smoking (Ennett and Bauman, 1994). The goal of this study was to conduct a partial replication of these findings. Methods: Data are from 1223 participants in the National Longitudinal Study of Adolescent Health. Spectral decomposition techniques identified friendship cliques, which were then used as the unit of analysis to examine influence and selection effects over a one-year period. Results: Non-smokers were more likely to become smokers if they initially belonged to a smoking (vs. non-smoking) group, and smokers were more likely to become non-smokers if they initially belonged to a non-smoking (vs. smoking) group, indicating an influence effect on both initiation and cessation. Further, group members who changed groups between waves were more likely to select groups with smoking behavior congruent to their own, providing evidence of a selection effect. Conclusions: While our results generally replicate the group analyses reported by Ennett and Bauman (1994), they suggest that peer influence and selection effects on adolescent smoking may be much weaker than assumed based on this earlier research. (C) 2010 Elsevier Ireland Ltd. All rights reserved.