Source: Educational Researcher, Vol. 37, No. 2, 65-75 (2008)
Value-added models help to evaluate the knowledge that school districts, schools, and teachers add to student learning as students progress through school. In this article, the well-known Education Value-Added Assessment System (EVAAS) is examined. The author presents a practical investigation of the methodological issues associated with the model. Specifically, she argues that, although EVAAS is probably the most sophisticated value-added model, it has flaws that must be addressed before widespread adoption. She explores in depth the shortage of external reviews and validity studies of the model, its insufficient user-friendliness, and methodological issues about missing data, regression to the mean, and student background variables. She also examines a paradigm case in which the model was used to advance unfounded assertions.