Districts nationwide have revised their educator evaluation systems, increasing the frequency with which administrators observe and evaluate teacher instruction. Yet, limited insight exists on the role of evaluator feedback for instructional improvement. Relying on unique observation-level data, we examine the alignment between evaluator and teacher assessments of teacher instruction and the potential consequences for teacher productivity and mobility. We show that teachers and evaluators typically rate teacher performance similarly during classroom observations, but with significant variability in teacher-evaluator ratings. While teacher performance improves across multiple classroom observations, evaluator ratings likely overstate productivity improvements among the lowest-performing teachers. Evaluators, but not teachers, systematically rate teacher performance lower in classrooms serving higher concentrations of economically disadvantaged students. And while teacher performance improves when evaluators provide more critical feedback about teacher instruction, teachers receiving critical feedback may seek alternative teaching assignments in schools with less critical evaluation settings. We discuss the implications of these findings for the design, implementation and impact of educator evaluation systems.