The Impacts of Teachers’ Union Reform on Student Achievement: Evidence from the Midwestern States

Purpose: Although research has investigated the influence of teachers’ unions on PK–12 school systems over several decades, the impact of reduced union power on students remains underexplored. This study addresses the limited and mixed evidence on how statewide teachers’ union reforms affect student academic outcomes. By examining comprehensive union reforms in two Midwestern states, we seek to clarify the broader consequences of weakening union power and to illuminate the mechanisms—such as staffing and resource shifts—through which these reforms shape student achievement. Research Methods/Approach: We used a difference-in-differences design with district-level longitudinal data from Wisconsin, Michigan, Iowa, and Ohio from 2009 through 2013. Findings: Our investigation revealed that statewide union reforms were statistically associated with lower student test scores, with a greater decline in districts serving a high concentration of Black and Hispanic students. The lower test scores were partially explained by concurrent reductions in district expenditure on instruction. Implications: This study suggests that weakening teachers’ unions may reduce instructional resources and eventually harm student learning. Researchers should continue investigating the mechanisms linking union reforms to educational outcomes, and policy makers should consider proactive and complementary investments to prevent unintended negative effects on students, particularly in disadvantaged districts, when designing or implementing union-related policy changes.