Improvement…means engagement in learning new practices that work, based on external evidence and benchmarks of success, across multiple schools and classrooms, in a specific area of academic content and pedagogy, resulting in continuous improvement of students’ academic performance over time. Improvement is not random innovation in a few classrooms or schools. It does not focus on changing processes or structures, disconnected from content and pedagogy. And it is not a single-shot episode. Improvement is a discipline, a practice that requires focus, knowledge, persistence, and consistency over time.

– Richard F. Elmore, School Reform from the Inside Out, p. 103-104