Our recent research uncovers peer effects in education as distinct from the contextual and other correlated influences. Our econometric strategy uses the topological structure of internet sites and network fixed effects to recognize each one of these effects separately.
Our analysis is manufactured possible through a distinctive database on friendship networks from the National Longitudinal Survey of Adolescent Health (AddHealth). The AddHealth database has been made to study the impact of the social environment (i.e. friends, family, neighbourhood and school) on adolescents’ behaviour in america by collecting data on students in grades 7-12 from a nationally representative sample of roughly 130 private and public schools in years 1994-95 (wave I). A subset of adolescents selected from the rosters of the sampled schools, was then interviewed again in 1995-96 (wave II), in 2001-2 (wave III), and again in 2007-2008 (wave IV). For our purposes, the most interesting facet of the AddHealth data may be the friendship information, which is situated upon actual friend nominations. It really is collected at wave I, i.e. when individuals were at school. Indeed, pupils were asked to recognize their finest friends from a school roster (up to five males and five females). Subsequently, we can reconstruct the complete geometric structure of the friendship networks.
In Calvó-Armengol et al. (2008), we exploit such information to check a peer-effect model which relates analytically equilibrium behaviour to network location. This analysis implies that the structure of friendships ties can be an important, therefore far unnoticed, determinant of a pupil performance at school. In Patacchini et al. (2011), we follow this type of research by exploiting the other AddHealth waves as a way to investigate whether such effect is carried as time passes. Indeed, the longitudinal structure of the survey provides information on both respondents and friends through the adulthood. Specifically, the questionnaire of wave IV contains detailed information on the best education qualification achieved.