Editorial

School districts are under pressure from the federal government, foundations, and states to include value-added assessment as a part of a teacher’s evaluation to meet the widely supported policy goal of identifying the most effective and the least effective teachers in a school system. On its face, the argument for value-added models (VAM) seems to make sense. How well a student does after a year with a teacher should serve as an indicator of how effective that teacher was. But by what measures? How valid are those measures? If the student measure is a score on a standardized test, what evidence do we have to indicate the standardized test accurately measures teacher effectiveness? Which students are being compared?

In his latest article, David Greene tells the story of a retired high school teacher named “Derrick” who became a substitute at a suburban high school.