Monday, January 25, 2016

Teacher Turnover of Low-Perfoming Teachers Has Positive Effects

In practice, teacher turnover appears to have negative effects on school quality as measured by student performance. However, some simulations suggest that turnover can instead have large, positive effects under a policy regime in which low-performing teachers can be accurately identified and replaced with more effective teachers.

This study examines this question by evaluating the effects of teacher turnover on student achievement under IMPACT, the unique performance-assessment and incentive system in the District of Columbia Public Schools (DCPS).

Employing a quasi-experimental design based on data from the first year years of IMPACT, the study find that, on average, DCPS replaced teachers who left with teachers who increased student achievement by 0.08 SD in math.

When the effects of lower-performing teachers who were induced to leave DCPS for poor performance are isolated, the study finds that student achievement improves by larger and statistically significant amounts (i.e., 0.14 SD in reading and 0.21 SD in math).

In contrast, the effect of exits by teachers not sanctioned under IMPACT is typically negative but not statistically significant.

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