In today’s New York Times David Leonhardt examines a new study from the D.C. school system on its teacher evaluation program called Impact, which was started under Michelle Rhee’s chancellorship. There’s been so much blowback against data-driven teacher evaluations, certainly in New Jersey as we begin the first year of full implementation of TEACHNJ. Some of that’s legitimate: a fumbling and obtuse DOE, obscure direction from all sides, the time-suck of SGO’s and SGP’s (Student Growth Objectives and Student Growth Percentiles), mixed signals from NJEA.  (I think everyone’s forgotten that the union actually crafted the legislation.)

So it’s heartening to hear some good news from D.C.  According to Leonhardt,

The study found that Impact caused more low-performing teachers to leave the school system than otherwise would have been expected. The program also seemed to improve teaching quality – as measured by classroom observations and test scores – of teachers with both strong and weak evaluation scores.  

“High-powered incentives linked to multiple indicators of teacher performance can substantially improve the measured performance of the teaching work force,” conclude the researchers, Thomas Dee of Stanford University’s Graduate School of Education and James Wyckoff of the Curry School of Education at the University of Virginia. Evaluation programs, they add, can bring “substantive and long-term educational and economic benefits” both by “avoiding the career-long retention of the lowest-performing teachers and through broad increases in teacher performance.”