Differential effects of private tutoring on facets of students' mathematics achievement: A longitudinal study

Private supplementary tutoring (PT) is practiced worldwide to improve students' academic performance and is highly prevalent in East Asia. However, studies have not clearly defined the effectiveness of PT. This study examined student-report questionnaires and school reports of mathematics achievements from approximately 2000 secondary school students to track retrospective longitudinal variations of PT over a year and analysed the differential effectiveness of regular mathematics PT participation on mathematics achievement at four hierarchical cognitive levels. Based on a sub-sample of students who regularly took PT in three consecutive periods (n = 773) as well as students who did not take PT (N = 758), the results indicated that the effect size of PT effectiveness decreased from low to high cognitive levels (from positive to negative). These results raise questions concerning the role of PT. This study provides an evidence-based assessment concerning the effectiveness of PT and highlights the implications for educational practice and future research.