This ongoing study describes a "loosely coupled-tightly coupled" approach to planning and implementing long-term, sustainable improvements in K-12 teaching and learning, and outlines the challenges and opportunities inherent in this model. The authors claim that involving site leaders, including teacher leaders, in determining inputs, resources, activities, processes, and initial outcomes, focusing on the impact question of what it will take to help all children succeed in mathematics, and using common measures of intermediate and long-range outcomes and impact can contribute to both changes in classroom practice and increased student achievement.