The Myth of Unions’ Overprotection of Bad Teachers: Evidence from the District–Teacher Matched Data on Teacher Turnover

This article examines the relationship between teachers’ unions and teacher turnover in U.S. public schools. The trade-off between teacher pay and employment predicts that unions raise the dismissal rate of underperforming teachers but reduce the attrition of high-quality teachers, as the higher wages unions negotiate provide districts strong incentives to scrutinize teacher performance during a probationary period while encouraging high-quality teachers to remain in teaching. Using the district–teacher matched data and a natural experiment, I find that, compared to less-unionized districts, highly unionized districts dismiss more low-quality teachers and retain more high-quality teachers, raising average teacher quality and educational outcomes.