We apply "value-added" models to estimate the effects of teachers on an outcome they cannot plausibly affect: student height. When fitting the relatively simple models that are widely used in educational practice to New York City data, we find the standard deviation of teacher effects on height is nearly as large as that for math and…

Estimates of teacher "value-added" suggest teachers vary substantially in their ability to promote student learning. Prompted by this finding, many states and school districts have adopted value-added measures as indicators of teacher job performance. In this paper, we conduct a new test of the validity of value-added models. Using…

The growing availability of data linking students to classroom teachers has made it possible to estimate the contribution teachers make to student achievement. While there is a growing consensus that teacher quality is important and current evaluation systems are inadequate, many have expressed concerns over the use of value-added measures (VAMs)…