An Elephant in the Classroom: Teacher Bias by Student SES or Ability Measurement Bias?

Teachers are academic merit gatekeepers. Yet their potential role in reproducing inequality via assessments was overlooked or not correctly identified, being an elephant in the classroom. This article teases if teacher grades and track recommendations are biased by student SES or unobserved ability, leading to overestimation in prior research. Using the German NEPS panel across elementary education, we identify student ability with multiple cognitive and noncognitive composite measures and an instrumental variable design. We further assess heterogeneity along the ability distribution to test whether, according to the compensatory hypothesis, teacher bias is largest among low-performers. First, accounting for measurement error, teacher bias declines by 40%, indicating substantial overestimation in previous studies. Second, it concentrates on underperformers, suggesting high-SES parental compensatory strategies to boost teacher assessments. Thus, families and teachers might influence each other in the evaluation process. We discuss the findings’ theoretical and methodological implications for teacher bias as an educational reproduction mechanism.