Teacher turnover matters

Last year, I wrote a series of posts calling teacher turnover the biggest problem we face in education, every word of which I still stand by, and would be willing to double down on (parts 1, 2, & 3). A new study backs that up, which Stephen Sawchuk wrote about recently for his Education Week blog:

When teachers leave schools, overall morale appears to suffer enough that student achievement declines—both for those taught by the departed teachers and by students whose teachers stayed put, concludes a study recently presented at a conference held by the Center for Longitudinal Data in Education Research...

Among their findings:

  • 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 effects were seen in both large and small schools, new and old ones.
  • The negative effect of turnover on student achievement was larger in schools with more low-achieving and black students.