Why do girls receive better grades in school? The role of students’ competencies, personality traits, school-related attitudes, and behaviour

This study investigates the gender gap in teacher-assigned grades in German and mathematics among 7th-grade students in Germany. Using rich data from the National Educational Panel Study (NEPS, N = 1,972 cases), we examine the extent to which observed differences in grades between boys and girls can be explained by student subject-specific competencies, personality traits, attitudes, and behaviours. We find a female advantage in language grades, whereas boys receive higher grades in mathematics. Results from the Karlson–Holm–Breen (KHB) decomposition method show that, in mathematics, the observed male advantage in grades is largely explained by boys’ higher subject-specific competencies, which account for approximately 60% of the gap. However, subject-specific interest also plays a non-negligible role in shaping teachers’ evaluations. In contrast, the female advantage in German grades is driven primarily by non-cognitive traits, such as conscientiousness (27%) and subject-specific interest (15%), while competencies in this domain contribute to a much smaller extent (12%). Moreover, the gender gap is most pronounced in the middle of the grade distribution, suggesting that teachers may apply broader evaluative criteria for students with average performance.