Each year, nearly a quarter of all New York City teachers move within their schools to a new grade-level assignment or a new subject. And those reassignments can depress their students’ achievement, concludes a study.
Teacher “churning,” as the study characterizes that kind of movement, is little studied, but extremely common. The new study is among the first to provide some preliminary evidence that this churn, on average, isn’t doing students any favors.
The research,, was written by Allison Atteberry of the University of Colorado at Boulder, Susanna Loeb of Stanford University, and James Wyckoff of the University of Virginia.
The trio looked at records on teachers in New York City from 1974 through 2010. A subset of those teachers, from 1999-2000, were linked to student-achievement records in grades 3-8, allowing the researchers to analyze the link between teacher churn and students’ test scores.
Overall, the study found that nearly 42 percent of teachers have new assignments in some way during a typical school year. And, of that number, more than half—54 percent—are changing assignments in the same school.
Much of that movement seems to be caused by teachers who leave a school or the profession, thereby requiring administrators to shuffle teachers around and hire new ones to make sure all classes are covered. But some schools tended to have far more switches than others, and black, Hispanic, and English-learner students were somewhat more likely to be assigned to a teacher moving to a new grade or subject in his or her school, but the overall difference was small.
The study estimates that the negative effect on student achievement of getting a churned teacher is about a quarter of the size of being assigned a brand-new teacher.
A version of this article appeared in the August 24, 2016 edition of Education Week as ‘Churn’ Among Teachers Seen to Affect Learning