We use six years of panel data on students and teachers to evaluate the effectiveness of recently hired teachers in the New York City public schools. On average, the initial certification status of a teacher has small impacts on student test performance. However, among those with the same experience and certification status, there are large and…

No Child Left Behind (NCLB) mandates a "highly qualified" teacher in every classroom. To meet the standard, teachers must have a bachelor's degree, be state-certified, and prove they know the subjects they teach, either by satisfying minimum course-taking requirements or passing a test in the subject they teach. But will compliance…