Norton E C, Lindrooth R C, Ennett S T
University of North Carolina at Chapel Hill, 27599-7400, USA.
Health Econ. 1998 Aug;7(5):439-53. doi: 10.1002/(sici)1099-1050(199808)7:5<439::aid-hec362>3.0.co;2-9.
This study examines whether the effects of peer substance use on adolescent alcohol and tobacco use are due to endogeneity of adolescents selecting their peer group. We analyzed data collected for a longitudinal analysis of a drug-use prevention programme for upper elementary school students. We used a two-step probit regression to control for the potentially endogenous explanatory variable peer substance use. Rigorous tests of endogeneity and the validity of the instrumental variables showed that controlling for the endogeneity of peer substance use to reduce bias is not worth the reduction in mean squared error in these data. Peer substance use has a positive and significant effect on adolescent substance use for both drinking and smoking. These results imply that peer influence is empirically more important than peer selection (endogeneity) in our sample of adolescents in grades 6-9. Living in a single-parent family was by far the strongest predictor of adolescent drinking and smoking.
本研究考察同伴物质使用对青少年酒精和烟草使用的影响是否归因于青少年选择其同伴群体的内生性。我们分析了为一项针对小学高年级学生的药物使用预防项目进行纵向分析而收集的数据。我们使用两步概率回归来控制潜在的内生解释变量同伴物质使用。对内生性和工具变量有效性的严格检验表明，在这些数据中，控制同伴物质使用的内生性以减少偏差并不值得以均方误差的减少为代价。同伴物质使用对青少年饮酒和吸烟的物质使用都有正向且显著的影响。这些结果表明，在我们6至9年级青少年样本中，同伴影响在经验上比同伴选择（内生性）更为重要。生活在单亲家庭是青少年饮酒和吸烟迄今为止最强的预测因素。
