Teacher turnover hurts student achievement, concludes a study presented at a Center for Longitudinal Data in Education Research conference, reports Teacher Beat.
Less-effective teachers are more likely to leave troubled schools, an earlier analysis found. But any benefits from losing the least-effective teachers are outweighed by having a staff in constant flux, the new research suggests.
• For each analysis, students taught by teachers in the same grade-level team in the same school did worse in years where turnover rates were higher, compared with years in which there was less teacher turnover.
• An increase in teacher turnover by 1 standard deviation corresponded with a decrease in math achievement of 2 percent of a standard deviation; students in grade levels with 100 percent turnover were especially affected, with lower test scores by anywhere from 6 percent to 10 percent of a standard deviation based on the content area.
The turnover effect was greater in schools with more low-achieving and black students, the study found.