Explanations about differences in drinking and smoking rates between educational tracks have so far mainly focused on factors outside the classroom. The extent to which these behaviors are rewarded with popularity within a classroom—so called popularity norms—and their interaction with individual characteristics could explain the observed differences in risk behavior. 1860 adolescents (M_age = 13.04; 50% girls) from 81 different classrooms reported three times during one academic year about their own and their classmates behavior. Overall, in vocational tracks popularity norms for alcohol and smoking were more positive and predicted classroom differences in alcohol and smoking. Knowledge about classroom processes can advance the field in unraveling the functional aspects of risk behavior in adolescence. Preregistration: The hypotheses and the analytical plan of this study were preregistered under number #39136 (https://aspredicted.org/blind.php?x=gx77p6).

迄今为止，关于教育轨道之间饮酒和吸烟率差异的解释主要集中在课堂之外的因素上。这些行为在课堂上的受欢迎程度（所谓的受欢迎程度规范）及其与个人特征的相互作用可以解释所观察到的风险行为差异。1860 青少年（M_岁） = 13.04; 50% 的女孩）来自 81 个不同的教室，在一个学年中 3 次报告了自己和同学的行为。总体而言，在职业赛道中，酒精和吸烟的流行规范更为积极，并预测了酒精和吸烟的课堂差异。关于课堂过程的知识可以推进该领域的发展，以揭示青春期风险行为的功能方面。预注册：本研究的假设和分析计划已在编号 #39136 (https://aspredicted.org/blind.php?x=gx77p6) 下预注册。