 How do classmates matter for the class-size effects?Ryuichi Tanaka and Tong Wang Economics of Education Review, 2025, vol. 108, issue C Abstract: This paper investigates the effect of class-size reduction on students’ academic outcomes, with a particular emphasis on its heterogeneity based on classmates’ characteristics. We estimate the causal effects of class-size reduction on students’ mathematics and language test scores by controlling for student and teacher fixed effects. To address potential endogeneity, we employ the predicted class size with a cap as an instrumental variable for the actual class size. Utilizing rich panel data on Japanese primary school students, our findings indicate a positive and robust average effect of class-size reduction on mathematics test scores. Furthermore, we find that classes with high-ability classmates benefit even more from class-size reduction in terms of language test scores. The effect of class-size reduction on mathematics test scores is found to depend positively on the ability of the lowest-achieving student in a class. Additionally, classes with a higher proportion of female students tend to benefit more from class-size reduction. Our results lend support to the theoretical framework proposed by Lazear (2001). Keywords: Education; Test scores; Class-size reduction; Ability; Heterogeneity (search for similar items in EconPapers) Downloads: (external link) Related works: Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text Persistent link: https://EconPapers.repec.org/RePEc:eee:ecoedu:v:108:y:2025:i:c:s027277572500069x DOI: 10.1016/j.econedurev.2025.102689 Access Statistics for this article Economics of Education Review is currently edited by E. Cohn More articles in Economics of Education Review from Elsevier |
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