The Importance of Ordinal Rank Among Peers: Focusing on Height and Income

We explore how elementary school students' classroom ordinal height or family income rank affects their future academic performance. Using a Korean panel dataset covering multiple classrooms within each school, we exploit the feature that two students with identical height or family income can be ranked differently based on their classroom assignment. We use classroom‐level dummy variables to compare students who share similar characteristics but have different classroom ranks, as these indicators absorb all linear differences across classrooms. Our results indicate that ordinal family income rank consistently and significantly impacts future academic performance, even after controlling for income levels, whereas ordinal height rank does not. Additionally, we show that a higher income rank is positively associated with students' motivation and parental support for academic achievement.