2010/09/30 by Hans Noel, Brendan Nyhan
Computer Science · Mathematics · Physics and Astronomy · Psychology · Social Sciences · #Attrition #Causal model #Computer science #Confounding #Demography #Econometrics #Electoral Systems and Political Participation #Friendship #Homophily #Leverage (statistics) #Longitudinal data #Mathematics #Psychology #Social Capital and Networks #Social and Cultural Dynamics #Social media #Social network (sociolinguistics) #Social psychology #Sociology #Statistics #cs.SI #physics.data-an #physics.soc-ph #stat.AP
paper · pdf · doi:10.1016/j.socnet.2011.05.003
26 pages, 4 figures
arxiv created 2011/06/17 · arxiv updated 2011/06/20 · openalex publication_date 2011/06/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
An increasing number of scholars are using longitudinal social network data to try to obtain estimates of peer or social influence effects. These data may provide additional statistical leverage, but they can introduce new inferential problems. In particular, while the confounding effects of homophily in friendship formation are widely appreciated, homophily in friendship retention may also confound causal estimates of social influence in longitudinal network data. We provide evidence for this claim in a Monte Carlo analysis of the statistical model used by Christakis, Fowler, and their colleagues in numerous articles estimating "contagion" effects in social networks. Our results indicate that homophily in friendship retention induces significant upward bias and decreased coverage levels in the Christakis and Fowler model if there is non-negligible friendship attrition over time.