In this paper, three rock star scholars examine the combined effects of teacher turnover and the “quality distribution of teacher transitions” using data from a large urban school district in Texas. Based on their results, they draw two main conclusions. First, teachers who leave the school system are generally less effective than those who stay. Second, teacher turnover nevertheless has a negative effect on schools where students are achieving at a low level—not because these schools are losing their “best” teachers but because they are losing more experienced teachers and because teachers who stay at these schools are often assigned to different grades in the wake of their colleagues’ departure, making them less effective. In short, low-achieving—mostly poor—schools are losing experience, not teaching talent per se.
On average, teachers who leave the Texas school system are roughly 50 percent of a standard deviation less effective than their colleagues—a massive difference with clear implications for policy. As the authors put it, the study highlights “the inadequacy of unfocused teacher policies, including universal pay increases, designed to reduce overall turnover without consideration of quality.”
In contrast, the 18 percent of teachers who switch to a different school or district during or after their first year on the job are actually more effective than those who stay behind. However, this finding does not hold for switchers in general, who are slightly less effective than those who stay (though still more effective than those who leave the system entirely). Again, low-achieving schools aren’t especially likely to lose effective teachers to other schools, but they are more likely to hire teachers who are newer to the field—and thus, less effective initially—as replacements.
Overall, the study’s findings “provide support for evaluation and compensation systems such as those implemented in Washington, D.C. and Dallas, Texas, that link pay increases with performance in an effort to retain, support and attract more effective teachers,” according to the authors. In particular, giving bonuses to effective teachers who remain at low-achieving schools seems like a promising strategy, in light of the damage schools suffer from teacher turnover. What reasonable observer could disagree?
SOURCE: Eric A. Hanushek, Steven G. Rivkin, and Jeffrey C. Schiman, “Dynamic Effects of Teacher Turnover on the Quality of Instruction,” National Bureau of Economic Research (July 2016).
