Does single-sex schooling improve students' physical fitness?: Evidence from a natural experiment in South Korea
利用韩国随机抽签分配中学的自然实验，发现男校显著提高男生身体素质，但女校对女生无显著影响。
• We study the effect of attending a single-sex school on the physical fitness of students. • Leverages a randomized lottery-based school assignment in South Korea. • All-male middle schools have a positive and significant impact on male students' physical fitness, whereas all-female middle schools show small and insignificant effects. Leveraging a randomized natural experiment, this study examines the impact of attending single-sex middle schools on students' physical fitness, measured through standardized nationwide physical tests. In South Korea, middle school students are assigned by lottery to either single-sex or coeducational schools within their designated school zones, providing an ideal setting to evaluate the effects of single-sex schooling. Using school-level data covering all middle schools, the study finds that boys attending single-sex schools achieve significantly higher pass rates on standardized physical fitness tests, suggesting improved physical fitness compared to their peers in coeducational schools. However, no similar improvement is observed for girls attending single-sex schools. These findings suggest that single-sex schooling has differential effects by gender, highlighting the need to further research to understand the mechanisms underlying these varied outcomes.