Teacher Bias, Socioeconomic Inequality, and the Role of Academic Reputations: Evidence from a Grading Reform

Prior research suggests teachers’ evaluations may be influenced by students’ socioeconomic background, yet most evidence comes from experimental settings that overlook biases arising in real student-teacher interactions. This article exploits a 2016 Danish reform that introduced external evaluation of a ninth-grade essay exam to examine whether teachers grade socioeconomically advantaged students more favorably than do external examiners. Using a difference-in-differences design comparing assessments affected and unaffected by the reform, I find that teacher involvement increases the socioeconomic grading gap by 15 percent to 20 percent. Further analyses show this effect is largely explained by objective measures of prior academic performance, suggesting it reflects not socioeconomic bias per se but teachers’ reliance on academic reputations when assigning grades.