0 The Impact of Teaching Disruptions on Student Achievement

We examine teaching disruptions and their impact on student achievement using data on teachers and students in New York City. By disruption, we mean a period of time when a student’s regularly assigned teacher is absent for an extended period of time or leaves their teaching position during the school year. These disruptions are uncommon; our analysis (focusing on teachers of math and English in grades 4 through 8) indicates that they affect less than three percent of classrooms per year. However, we find these disruptive events have significant negative effects, lowering student achievement by 0.06 and 0.03 standard deviations in math and English Language Arts, respectively. This suggests that policies which help maintain instructional quality during periods of teacher absence and disruption can have significant benefits to students. Additionally, we find evidence that teacher health can impact student achievement above and beyond any relationship it bears with disruptions and absences. Specifically, we find student achievement is significantly lower when teachers go on medical leave, go on maternity leave, or take additional absences for medical reasons after students have already been tested. All of these estimates are identified from variation within teachers, which suggests that strategies for measuring the causal impact of absences that assume static selection with regard to teacher quality may be biased