Researchers and policymakers often assume that teacher turnover harms student
achievement, but recent evidence calls into question this assumption. Using a unique identification
strategy that employs grade-level turnover and two classes of fixed-effects models, this study
estimates the effects of teacher turnover on over 850,000 New York City 4th and 5th grade student
observations over eight years. The results indicate that students in grade-levels with higher turnover
score lower in both ELA and math and that this effect is particularly strong in schools with more
low-performing and black students. Moreover, the results suggest that there is a disruptive effect of
turnover beyond changing the distribution in teacher quality.