Most teachers become more effective with experience, while other teachers never become effective at all. The new ESSA regulations require that states now define “ineffective,” “inexperienced,” or “out-of-field teachers” and work to make sure that effective teachers are placed into high-poverty, high-minority classrooms in an equitable fashion. States are now tasked with creating plans that effectively measure teacher quality and ensure that all students have equal access to effective teachers, who have a strong impact on academic achievement. Some states are doing a better job than others, according to the National Council on Teacher Quality.