Tenure or Turnover?

It seems obvious that teacher turnover drags down student performance, right? Not so fast.

In theory, teacher turnover could have either a positive or negative impact on students. On one hand, teacher turnover might produce better matches between schools and teachers and result in fresh perspectives. On the other hand, high teacher turnover could decrease student-teacher trust and interrupt institutional knowledge creation.

Empirical research offers support for both theories. The results of Hanushek and Rivkin (2010) suggest that teacher turnover has the potential to boost student performance in disadvantaged urban schools because poorly performing teachers are more likely to leave than their higher-achieving counterparts. On the contrary, Guin (2004) finds a strong negative correlation between teacher turnover and student performance.

A 2011 National Bureau of Economic Research (NBER) working paper “How Teacher Turnover Harms Student Achievement” attempts to resolve this debate in a more comprehensive study of teacher turnover. Matthew Ronfeldt, Hamilton Lankford, Susanna Loeb, and James Wyckoff examine the impact of teacher turnover on the math and English Language Assessment (ELA) test scores of over 600,000 4th and 5th grade students in New York City.

The research team finds that students’ math and ELA scores are significantly lower when there is a high level of teacher turnover within each grade level. The lower effectiveness of replacement teachers, however, only partially explains the poorer post-turnover student performance. This suggests that teacher turnover has a more general disruptive effect on students and that finding qualified teacher replacements is an insufficient solution.

Turnover has the largest negative effects at big schools, old schools, and schools with high proportions of low-achieving and Black students. Schools with higher levels of turnover tend to have fewer higher performing and Asian students, more poor, Black, and Hispanic students, and more student absences and suspensions. Put simply, high levels of teacher turnover are much more common for schools that serve predominately poor, Black, and Hispanic children, exactly where turnover has the most adverse effects on student performance.

The results of the research help clarify the impact of teacher turnover on student performance and present a more nuanced picture of why teacher turnover matters.