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…

National Board Certification represents one of the most significant reform efforts in the area of teacher quality in the last two decades. Since the National Board for Professional Teaching Standards (NBPTS) certified its first round of teachers in 1995, approximately 24,000 teachers have become certified at a cost to the country of well over $200…