國中生放學後做家事時間變化對學習成就的影響是一個值得探究議題。若將學生的家庭社經地位納入與此議題分析會如何呢？本研究以基隆市國中生學習狀況資料庫，分析1,234名學生在五學期放學後做家事時間變化軌跡，並瞭解家庭社經地位與做家事時間變化對學習成就的影響，研究顯示：國中生放學後做家事時間變化軌跡呈W型趨勢；七年級與八年級下學期做家事時間明顯高於九年級上學期，其他各學期之間沒有明顯不同，七年級下學期最多，九年級上學期最少。學生的家庭社經地位愈高，做家事時間愈少，而家庭社經地位對做家事時間變化沒有明顯影響，不過家庭社經地位仍對學習成就有顯著正向影響。七年級做家事時間愈多，九年級的學習成就愈不好，但做家事時間變化對於學習成就沒有明顯影響；七年級的做家事時間在家庭社經地位與學習成就之間具有部分中介效果，然而做家事時間變化沒有中介效果。本研究特色在於發現，學生放學後做家事時間變化呈W型趨勢，家庭社經地位僅對七年級做家事時間有負向影響，對後續學期變化則沒有明顯影響；七年級的做家事時間愈多，九年級學習成就愈不好，但做家事時間長期變化對學習成就沒有明顯影響。

The impact of changes in the time that junior high school students spent doing housework after school on their academic achievement is an issue worth exploring. What if students’ family socioeconomic status was included in the analysis of this issue? The main purpose of this study is to use the learning status database of junior high school students in Keelung City to analyze the trajectory of the time spent doing housework after school among 1,234 students in the five semesters, and to understand the impact of changes in family socioeconomic status and time spent doing housework on academic achievement. The study showed: Junior high school students the trajectory of the time students spent doing housework after school showed a W-shaped trend; the time spent doing housework in the second semester of seventh grade and eighth grade was significantly higher than that in the first semester of ninth grade, while there was no significant difference between other semesters. The second semester of seventh grade had the most time doing housework. The first semester of ninth grade was the least. The higher the socioeconomic status of a student’s family, the less time they had to do housework. The socioeconomic status of the family had no significant impact on changes in time spent doing housework. However, the socioeconomic status of the family still had a significant positive impact on academic achievement. The more time spent doing housework in seventh grade, the worse the academic achievement in ninth grade. However, changes in housework time had no significant impact on academic achievement; the time spent doing housework in seventh grade had a partial mediating effect between family socioeconomic status and academic achievement. However, changes in housework time had no mediating effect. The characteristic of this study was that it was found that the time students spent doing housework after school showed a W-shaped trend over time. Family socioeconomic status only had a negative impact on the time spent doing housework in seventh grade, but had no significant impact on changes in subsequent semesters; The more time spent doing housework, the worse the academic achievement in ninth grade. However, long-term changes in time spent doing housework have no significant impact on academic achievement.