Friday, January 6, 2012

Education Research Report: THE LONG-TERM IMPACTS OF TEACHERS

Education Research Report: THE LONG-TERM IMPACTS OF TEACHERS:

THE LONG-TERM IMPACTS OF TEACHERS

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TEACHER VALUE-ADDED AND STUDENT OUTCOMES IN ADULTHOOD


Many policy makers advocate increasing the quality of teaching, but there is considerable debate about the best way to measure and improve teacher quality. One method is to evaluate teachers based on their impacts on students’ test scores, commonly termed the “value-added” (VA) approach. A teacher’s value-added is defined as the average test-score gain for his or her students, adjusted for differences across classrooms in student characteristics such as prior scores. School districts from Washington D.C. to Los Angeles have begun to use VA to evaluate teachers. Proponents argue that using VA can improve student achievement (e.g. Hanushek 2009), while critics argue that test score gains are poor proxies for a teacher’s true quality (e.g. Baker et al. 2010).

The debate about VA stems from two fundamental questions. First, does VA accurately measure teachers’