Bargaining for Success: Examining the Relationship Between Teacher Unions and Student Achievement

While many previous studies have identified a positive relationship between teachers unions and student achievement on standardized tests, little research to date has explored the channels through which unions might actually affect achievement. Utilizing multilevel random intercept models, we examine the effects of two categories of items commonly negotiated in teacher contracts-"industrial union" items and "professional union" items-on individual student math scores. Further, we assess the ability of these two clusters of variables to explain the positive union effect found in previous research. The results confirm that teachers unions are positively associated with student achievement and suggest that the industrial model explains moderately more of the union effect than the professional model; however, only the combination of both models is capable of reducing the union effect to nonsignificance. These findings are also confirmed in a supplemental analysis utilizing instrumental variables to account for the possibility of endogeneity. Finally, a decomposition of the union effect suggests that teachers unions are most beneficial to middle- and high-achieving students. We conclude that through industrial and professional bargaining, teachers are able to secure higher salaries, credentialing, and greater autonomy which lead to improved student achievement.