By Stephen Sawchuk
The District of Columbia's closely-watched system for evaluating teachers and providing bonus pay appears to have motivated weak teachers to make improvements, and to spur already-effective teachers to even higher levels of performance, a new study concludes.
Teachers on the cusp of dismissal under D.C.'s IMPACT evaluation system improved their performance by statistically significant margins, as did those on the cusp of winning a large financial bonus, according to the study, which was published as a working paper Thursday by the Cambridge, Mass.-based National Bureau of Economic Research.
The provocative study raises new questions about how recently revamped teacher-evaluation systems—and pay schedules linked to them—shape teacher behavior. It is among the first research studies to look at teacher evaluation empirically.
As an actual policy rather than a pilot, IMPACT was somewhat different in scope from other programs aimed at boosting teacher skill. Teachers with lower initial ratings also received access to instructional coaches to improve areas of their practice, one possible explanation for the gains.
"All of the actors involved are taking this system seriously, and it's in those situations where you might expect greater responses to the incentives," said James H. Wyckoff, a University of Virginia professor of education and policy, and one of the study's authors.
The study does not look at whether the improvement in teachers' scores translated into more learning for their students, though, and the researchers cautioned that the results apply only to the populations close to the performance thresholds studied. They do not depict an "overall" effect of IMPACT.