NEPC Review: Have We Identified Effective Teachers? and A Composite Estimator of Effective Teaching
The Gates Foundation’s Measures of Effective Teaching (MET) project was a multi-year study of thousands of teachers in six school districts that concluded in January 2013. This review addresses two of the final MET research papers. One paper uses random assignment to test for bias in teachers’ value-added scores. The experimental protocol was compromised, however, when many students did not remain with the teachers to whom researchers had assigned them; other students and teachers did not participate at all. This prevents conclusive answers to the questions of interest. The second paper examines how best to combine value-added scores, classroom observations, and student surveys in teacher evaluations. The data do not support the MET project’s premise that all three primarily reflect a single general teaching factor, nor do the data support the project's conclusion that the three should be given roughly equal weight. Rather, each measure captures a distinct component of teaching. Evaluating teachers requires judgments about which components are the most important, judgments that are not much informed by the MET’s masses of data. While the MET project has brought unprecedented vigor to teacher evaluation research, its results do not settle disagreements about what makes an effective teacher and offer little guidance about how to design real-world teacher evaluation systems.