教师在职学历提升对学生成绩的促进作用:基于甘肃农村的证据

The Effect of Teachers’On-the-Job Training on Students’AcademicPerformance:Based on the Evidence from the Rural Areas in Gansu Province

基于甘肃基础教育调查两轮追踪调查的数据,利用"教师—学生—学科"配对样本的固定效应估计和工具变量法,考察当地农村教师工作后学历提升活动对其教学效能的影响。研究发现,教师职后学历提升对学生测试成绩具有显著的促进作用。与教师不参加职后学习和培训的情形相比,当前学历所对应的受教育年限比职初水平每增加一年,其所教学生在相关学科的标准化测验中表现高0.2~0.3个标准差。对基于不同方法所得结果具有差异的机制分析发现:《中华人民共和国教师法》对中小学教师行业准入的学历资格做出具体规定后,相当一部分初始学历不达标的农村教师通过职后学历提升的形式对此政策做出了行为反应,忽视这一部分群体的特殊性将严重偏估甚至误判教师在职人力资本投资的生产率价值。

Based on longitudinal data from Gansu Survey of Children and Families(GSCF,2004—2007),the paper investigates how teaching effectiveness measured by students’academic performance will be affected by on-the-job re-education of teachers by employing“teacher-student-subject”fixed effect combined with instrument variable estimations.The author finds that education upgrading practices after entering teaching profession significantly associated with higher productivities.Counterfactual result indicates that each year of educational change upward above the mean after initial job placement for teachers will produce student testing scores 0.2~0.3 standard deviations higher,other things being equal.The sharp contrasts between OLS and FE-IV within-estimators illustrate the severity of model mis-specifications due to endogeneity of teachers’motivations of upgrading education qualifications,especially for those who joined teaching profession at earlier years before implementation of national regulations on professional qualifications standards which specifies the minimum education requirements for teachers serving different levels of pupils,these cohorts were heavily hit by this natural experiment and were later obliged to react to the policy shock by the approach of on-the-job skills updates,the negative selection of whom definitely lead to under-estimation of real effects of completing an advanced degree above that of at the beginning of the career in OLS specifications.