基础教育中的同伴效应估计

对基础教育阶段不良同伴带来的短期和中长期效应的评估已经成为劳动经济学的热点话题.文章根据最新的2014年中国教育追踪调查( China Education Panel Survey, CEPS)微观数据,考察了不良同伴对学生标准化考试成绩的影响.为了克服反射(reflection)和自选择问题带来的估计偏误,文章依据班级上不良学生的比例而非传统文献采用的同伴成绩来刻画学生所处的班级环境,并控制了组群的自然特征.在控制学生个体特征和家庭因素后发现,学生所在班级中存在不良同伴,会对学生自身的学习成绩造成显著的负面影响,这一作用在高年级(初三)表现得尤为明显.班级不良同伴比例提高10%会带来平均成绩下降约2分.分样本的回归显示,男性学生、家庭经济状况不佳的学生和住校生的学习成绩对班级不良同伴的反应更敏感.而学校类型的异质性分析则表明,同伴效应在办学情况较差的学校和乡镇/农村学校表现得更明显.进一步的分位数回归结果表明,不良同伴产生的负面效应对成绩较差的学生影响更大.文章的研究发现有利于丰富学界对教育生产函数的认识,也为今后的教育政策提供有益参考.

The Evaluation of Peer Effects in Primary Education

Summary: The evaluation of the short-term and long-term of disruptive peer effects in the primary edu-cation stage has become a hot topic in labor economics. Based on the latest Chinese Education Panel Survey(CEPS)data in 2014,this paper empirically examines the impact of disruptive peers on the student test scores. When studying the peer effects,there are two key problems to solve,reflection and self-selection. The so-called "reflection" refers to the problem of mutual influences between peers. It is essentially a reverse causal-ity problem that is often encountered in the setting of econometric models,because it is difficult to tell wheth-er the disruptive students have an impact on other students or some students have a bad influence on the sur-rounding students,which leads to a biased and inconsistent estimator if researchers use the surrounding stu-dents' performance to explain other students'. Self-selection mainly refers to the fact that families don't choose schools and classes completely randomly. In order to overcome the estimation bias caused by the problem of reflection and self-selection,we define the class environment as the proportion of disruptive students in the class rather than the peer achievement used in the traditional literature, and we also control the cohort features. After controlling the individual and family factors,we find that students exposed to a disruptive environ-ment have a significant lower education performance. This effect is more significant for the third grade stu-dents in the junior high school. One percent increase of the disruptive peers will result in about 0.2 decreasing in the average standardized test score. The result also shows that the acadamic performance of male students, students with poor family conditions and boarding students is more sensitive to class peers. The heterogeneity analysis of school types shows that peer effects are more obvious in schools with poor education and in town-ship/rural schools. Furthermore,quantile regression results show that the negative effect of disruptive peers has a greater impact on poorly performing students. This paper is helpful to enrich the academic cognition of educational production function and provide a useful reference for future education policy. The underlying implication of our study is that if there are reason-able and feasible policies that can change students' class environment or a more reasonable class division plan,it will effectively improve the educational achievements of students. In addition,the attention to students' family environment should be strengthened,especially those students who perform poorly in school,and strengthening communication and psychological counseling will bring about significant spillovers.