It appears to be an important research study, but in the sense of implication to educational policy, not so much. The reason is, for one, the use of value-adde

It appears to be an important research study, but in the sense of implication to educational policy, not so much. The reason is, for one, the use of value-added measurement does not have a significant role as many would think. There is not a signle state in the U.S. use VAM as a single measure of teacher performance, nor a determinant factor in teacher firing or promotion. It is always mixed with other quantitative and / or qualitative measures (which usually are no better than VAM). The second reason is, the research community has not find a better replacement yet. We always know we cannot directly use student achievement, now we know we cannot trust a more complicated measure such as VAM which takes into account of student history and other factors.