As states and districts implement more rigorous teacher evaluation systems, measures of teacher performance are increasingly being used to support instruction and inform retention decisions. Classroom observations take a central role in these systems, accounting for the majority of teacher ratings upon which accountability decisions are based.…

Despite policy efforts to encourage multiple measures of performance in newly developing teacher evaluation systems, practical constraints often result in evaluations based predominantly on formal classroom observations. Yet there is limited knowledge of how these observational measures relate to student achievement. This article leverages the…

Evidence that teachers' short-term instructional effects persist over time and predict substantial long-run impacts on students' lives provides much of the impetus for a wide range of educational reforms focused on identifying and responding to differences in teachers' value-added to student learning. However, relatively little research has…