作业时间对学生学业成绩的影响及其机制研究——兼论“双减”政策背景下的最优作业量

Research on the Influence of Homework Time on Students’ Academic Achievement and Its Mechanism: Also on the Optimal Homework Time under the Background of “Double Reduction” Policy

基于中国教育追踪调查数据,本文探讨了作业时间对初中生学业成绩的影响。研究发现,七年级和九年级学生平均每天作业时间为2.28小时和2.67小时,远超“双减”政策有关初中生作业时间不得超过90分钟的规定。作业时间在不同性别、年级、地区的学生组别之间存在显著差异。作业时间对初中生学业成绩的影响呈倒U型,门槛回归分析表明,初中生每天作业时间小于0.96小时,作业时间对学业成绩的促进效果最大;超过0.96小时,作业时间对学业成绩的促进效果下降;当超过4.07小时,作业时间对学业成绩具有负效应。中介机制分析发现过长的作业时间会导致学生出现生活无趣、不快乐、沮丧、悲伤等负面情绪,并剥夺学生正常成长所需的睡眠时间。研究发现,初中生每天最佳作业时间约为1小时,这与“双减”政策关于初中生每天作业时间最多不超过90分钟的规定是一致的。

Based on the baseline survey data of CEPS from 2013 to 2014, this paper explores the impact of homework time on academic performance. Firstly, the average daily homework time of seventh and ninth grade students are 2.28 hours and 2.67 hours respectively, which exceeded the stipulation of “Double reduction policy” that the homework is no more than 1.5 hours for junior high school students. The influencing factor analysis shows that there are group differences among students of different genders, grades and regions. Secondly, the OLS regression based on the Value-added Model shows the effect of homework time on academic performance is inverted U type. Lastly, the threshold regression and mediation effect analysis found that when homework time less than 0.964 hours is at upward period, and homework time has the greatest promotion effect on their academic performance;when homework time is between 0.96 hours and 4.07 hours a day, the improvement effect of homework time on academic performance is limited;when homework time is more than 4.07 hours, students’ academic performance will be reduced, because homework can leads to students’ negative emotions such as dull life, unhappiness, depression, sadness, deprived students of adequate sleep in the process of growing up. Therefore, the best homework time for junior high school students is about 1 hour, which is consistent with the rule of “Double reduction policy”.