Educators raise concerns about what happens to students when they are exposed to new or new-to-school teachers. However, even when teachers remain in the same school they can switch roles by moving grades and/or subjects. We use panel data from New York City to compare four ways in which teachers are new to assignment: new to teaching, new to…

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…