title: A dynamic model of US adolescents' smoking and friendship networks.
abstract: OBJECTIVE
  We investigated the associations between smoking and friend selection in the social networks of US adolescents.
  
  
  METHODS
  We used a stochastic actor-based model to simultaneously test the effects of friendship networks on smoking and several ways that smoking can affect the friend selection process. Data are from 509 US high school students in the National Longitudinal Study of Adolescent Health, 1994-1996 (46.6% female, mean age at outset=15.4 years).
  
  
  RESULTS
  Over time, adolescents' smoking became more similar to their friends. Smoking also affected who adolescents selected as friends; adolescents were more likely to select friends whose smoking level was similar to their own, and smoking enhanced popularity such that smokers were more likely to be named as friends than were nonsmokers, after controlling for other friend selection processes.
  
  
  CONCLUSIONS
  Both friend selection and peer influence are associated with smoking frequency. Interventions to reduce adolescent smoking would benefit by focusing on selection and influence mechanisms.
authors.affiliation: School of Social and Family Dynamics, Arizona State University, Tempe, AZ 85287-3701, USA. david.schaefer@asu.edu
authors.forename: David R
authors.initials: DR
authors.lastname: Schaefer
authors.forename: Steven A
authors.initials: SA
authors.lastname: Haas
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Bishop
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D005260:Female; D033062:Friends / Q000523:psychology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015233:Models, Statistical; D010379:Peer Group; D015995:Prevalence; D012907:Smoking / Q000523:psychology*; D012944:Social Support; D013269:Stochastic Processes; D014481:United States; D055815:Young Adult