倪晨旭,王震

• 1:中国社会科学院大学经济学院
• 2:中国社会科学院经济研究所

摘要(Abstract)：

过往的同伴效应研究多数基于假设“群体内所有个体存在同质化的互动与影响”来关注同学群体，然而现有文献指出，关系亲密的好友同伴效应会更加强烈。因此，本文聚焦学生的好友圈，以中国初中学生为对象，试图回答好友性别对学生成绩的影响与作用机制。本文发现每增多一个异性好友或同性好友都会使初中学生的语数英成绩显著下降，三科总分分别下降11.8分和3.7分。机制分析表明，成绩下降主要由时间挤出效应解释，与朋友交往并没有影响“强迫性学习”时间，“自主性学习”时间的挤出才是好友性别溢出的负面效应的真正原因。拥有更多异性好友使得恋爱可能性提高加重了这种负面效应，而与更多好友交往使学生在学校感受到友好氛围则抵消了部分影响。为全面理解初中生交友的溢出效应，本文还进一步讨论了朋友性别对学生认知与非认知能力的影响。本文推广了同伴效应的适用范围，对理解我国学生在义务教育阶段的朋友交往有重要意义。

关键词(KeyWords)： 同伴效应;学习成绩;非认知能力;朋友交往

Abstract:

Keywords:

基金项目(Foundation):

作者(Author): 倪晨旭,王震

参考文献(References)：

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• (1)这种效应也被称为“社会乘数”,同伴和自己的行为特征会相互影响(Angrist,2014)。
• (2)Gong et al.(2018)和Gong et al.(2021)每次从67个学校中随机地删除2个、用余下65个学校的学生作样本估计基准模型,这样共操作2211(C■)次。由于是随机删除,他们的2211个样本中可能存在相同的。我们采用的是不重复删除,6216个样本中不存在相同的,正好穷尽所有组合。跟Gong et al.(2018)和Gong et al.(2021)一样,我们每次删除2个学校的学生是为了保证样本规模。