Our guest author today is Dan Goldhaber, Director of the Center for Education Data & Research and a Research Professor in Interdisciplinary Arts and Sciences at the University of Washington Bothell.
Let me begin with a disclosure: I am an advocate of experimenting with using value added, where possible, as part of a more comprehensive system of teacher evaluation. The reasons are pretty simple (though articulated in more detail in a brief, which you can read here). The most important reason is that value-added information about teachers appears to be a better predictor of future success in the classroom than other measures we currently use. This is perhaps not surprising when it comes to test scores, certainly an important measure of what students are getting out of schools, but research also shows that value added predicts very long run outcomes, such as college going and labor market earnings. Shouldn’t we be using valuable information about likely future performance when making high-stakes personnel decisions?
It almost goes without saying, but it’s still worth emphasizing, that it is impossible to avoid making high-stakes decisions. Policies that explicitly link evaluations to outcomes such as compensation and tenure are new, but even in the absence of such policies that are high-stakes for teachers, the stakes are high for students, because some of them are stuck with ineffective teachers when evaluation systems suggest, as is the case today, that nearly all teachers are effective.