Teacher Sorting and Inequalities in Student Achievement: Unequal Exposures and Differential Returns to Teacher Qualifications

Teachers play a formative role in shaping children’s school experiences and ultimately, their educational outcomes. In this study, I use full population Danish administrative data to explore the consequences of unequal access to qualified teachers in three steps. First, I document strong patterns of teacher–student sorting in Denmark, one of the world’s most equal societies and generous welfare states. In short, teachers from higher socioeconomic backgrounds and with higher prior academic achievements tend to select into schools serving high-achieving children from privileged backgrounds. Second, I investigate the effect of exposure to teachers with different qualifications on students’ test score performance. To facilitate causal estimates, I exploit plausibly exogenous shocks to teacher changes induced by parental leave spells, which, I show, are unrelated to an extensive set of observed classroom characteristics, including student well-being and measures of classroom climate. Third, I explore differentials in the impact of teacher qualifications by students’ socioeconomic background. I find no consistent evidence of differential teacher effects, implying that teacher-induced learning inequalities are mainly driven by unequal exposure to highly qualified teachers, rather than unequal returns to qualifications. This suggests that policies equalizing access to qualified teachers may reduce learning disparities.