Teacher value-added models (VAMs) must isolate teachers' contributions to student achievement to be valid. Well-known VAMs use different specifications, however, leaving policymakers with little clear guidance for constructing a valid model. We examine the sensitivity of teacher value-added estimates under different models based on whether they…

While students begin schooling with high engagement levels, these levels begin to drop in the middle years of schooling but appear to recover somewhat in 10th grade, suggesting that the middle years of schooling are an especially vulnerable time in terms of student engagement (Willms et al., 2009). Moreover disengagement is most common in students…