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Revisiting The Widget Effect: Teacher Evaluation Reforms and the Distribution of Teacher Effectiveness

In 2009, the New Teacher Project’s The Widget Effect documented the failure of U.S. public school districts to recognize and act on differences in teacher effectiveness. Authors Matthew Kraft and Allison F. Gilmour revisit these findings by compiling teacher performance ratings across 24 states that adopted major reforms to their teacher evaluation systems. In the vast majority of these states, the percentage of teachers rated unsatisfactory remains less than 1%. However, the full distributions of ratings vary widely across states, with 0.7% to 28.7% rated below proficient and 6% to 62% rated above proficient. The report presents original survey data from an urban district illustrating that evaluators perceive more than 3 times as many teachers in their schools to be below proficient than they rate as such. Interviews with principals reveal several potential explanations for these patterns.