Influence of different types of interclass ability grouping on students’ academic achievement in mathematics: evidence from the Confucian Asian cluster

Ability grouping has attracted worldwide attention in relation to various subjects among different countries and regions. However, few studies have focused on the relationship between ability grouping and students' mathematical academic achievement in the Confucian Asian countries. Thus, in this study, we aimed to determine how different types of interclass ability grouping impact students' academic achievement in mathematics. We analysed PISA2022 data for 34,968 students from 923 schools in six countries and regions, including Hong Kong, Macau, Taipei, Japan, South Korea, and Singapore, using a hierarchical linear model and propensity score matching. We found that overall, multi-level ability grouping reduced students' mathematics achievement, and this negative effect was particularly significant among high-ability students, while it promoted the mathematics achievement of low-ability students to some extent.