Arguably the most important educational resource is teachers. Teachers and teaching quality are a central feature of the No Child Left Behind Act of 2001 (NCLB) which requires a "highly qualified teacher" in every core academic classroom. Many states and large districts also have policies in place to attract qualified teachers to…

Richard Murnane observes that the American ideal of equality of educational opportunity has for years been more the rhetoric than the reality of the nation's political life. Children living in poverty, he notes, tend to be concentrated in low-performing schools staffed by ill-equipped teachers. They are likely to leave school without the skills…

Most studies that have fueled alarm over the attrition and mobility rates of high-quality teachers have relied on proxy indicators of teacher quality, which recent research finds to be only weakly correlated with value-added measures of teachers' performance. We examine attrition and mobility of teachers using teacher value-added measures for…