Effective professional development that equips teachers with new skills and knowledge and utilizes coaching to assist teachers with application results in a 95% mastery of those skills and knowledge (Joyce & Showers, 2002). Through a four-step continuous improvement process, STEP leads educators through each phase in following a natural learning progression towards improvement. It provides a structured yet nimble way to conduct PLCs that attends to the technical and social aspects of improvement and ultimately helps answer the central question: How do we know when a change is an improvement?