Dear all, Please join us for the Applied Statistics Workshop (Gov 3009) this Wednesday, October 19 from 12.00 - 1.30 pm in CGIS Knafel Room 354. Weihua An, a Lecturer in the Department of Sociology at Harvard University, will give a presentation entitled "Peer Effects on Adolescent Smoking and Social Network-Based Interventions". As always, a light lunch will be provided. The abstract for the presentation is: *This study addresses a fundamental question in social network analysis: whether and to what extent peers affect a person's wellbeing. More specifically, it attempts to identify and quantify peer effects on smoking among adolescents. * * * *Based on the causal inference terminology, a systematic framework to study causal peer effects was developed to distinguish several types of peer effects, including peer effects under control, peer effects under treatment, etc. To overcome the difficulties in identifying peer effects with observational data, a novel field experiment was conducted with a partial treatment group design specifically tuned to estimate peer effects. * * * *More specifically, a smoking prevention intervention composed of distributing smoking prevention brochures and hosting health education workshops was assigned to partial randomly chosen members in a number of classes in six middle schools in China where the experiment was fielded. The goal was to study how the information contained in the intervention was spread across students and how it affected their information, knowledge, intention, and behavior regarding smoking. To accelerate or reinforce the diffusion, central students or students with their close friends as identified based on their social network information were also chosen respectively to receive the intervention in different treated classes. * * * *Descriptive analysis provided strong support for peer effects on the initiation and maintenance of adolescent smoking. Further statistical analysis showed that compared with students in the control classes, students whose classmates were randomly chosen to receive the intervention but who did not receive the intervention themselves were more likely to exchange information about the intervention with other students and to remain non- smokers or change to non-smokers overtime. It was also found that the social network- based interventions did not consistently bring significant added value in all the outcomes of interest and their benefits mainly concentrated on lowering students' intention to smoke and decreasing smokers' popularity. * * * *Special attention will be paid in the presentation to elaborating how to choose central students and student groups in a social network. * An up-to-date schedule for the workshop is available at http://www.iq.harvard.edu/events/node/1208. Best, Konstantin -- Konstantin Kashin Ph.D. Student in Government Harvard University Mobile: 978-844-0538 E-mail: kkashin(a)fas.harvard.edu Site: http://people.fas.harvard.edu/~kkashin/