Frequently Reassigning Teachers Limits Their Improvement

Experienced teachers make a difference in student performance, but their experience matters most if they have continued to teach the same grade, according to a new study by a University of Illinois at Chicago researcher.

Students whose teachers have not switched grades show greater improvement in test scores than students in similar classrooms with equally experienced teachers who switched grades frequently. The study is published in the April print edition and online in the American Economic Journal: Applied Economics.

“The results demonstrate that part of teacher improvement is due to specific knowledge and skills regarding a particular grade,” says study author Ben Ost, UIC assistant professor of economics.

“Switching teachers around prevents them from applying this knowledge and skill.”

On average, teachers improve as they gain experience, Ost said, but the rate of improvement is faster if they continue to teach in the same grade.

“This means that if two teachers start off as equally effective, the one that repeatedly teaches the same grade will become a more effective teacher over time,” Ost said.

The study looked at approximately 500,000 students in grades 3-5 in North Carolina. The North Carolina Educational Research Data Center compiled the data.

Similar studies had found that teachers generally improve with experience, but none had investigated whether improvement depended on what grade the teacher taught, Ost said.

“The fact that teachers improve with experience is commonly cited as one reason that teacher attrition is problematic,” he said. “This paper shows that frequently reassigning a teacher to a new grade has consequences similar to teacher attrition, because his or her grade-specific skills are wasted.”