A national literacy professional development project reduced the achievement gap for students experiencing difficulties in reading or writing in 91 of New Zealand's schools. It was based on two premises: coherence within and between the multiple levels of the schooling and educational administration systems, and a focus on evidence-informed inquiry into effectiveness at each level of the system. Over the 2 years of the project's operation, these two premises interacted in ways that led to ongoing problem identification. Examples include how students understood their learning, how teachers and school leaders taught these students, how professional development facilitators changed their approaches, and how the project leaders and policy makers developed new systems for learning. Solutions were actively and collaboratively sought at all levels. Research data included assessment of student literacy in reading or writing; participant observations of the project leadership operations; interviews with principals, literacy leaders, and teachers; scenario responses; and interviews with facilitators. An analysis of facilitator practice early in the project illustrates how project leadership responded to the problems identified. Ongoing learning resulted from the interaction between facilitator feedback to teachers and their reflective responses to the observations of that feedback. Important to the success of this program is the continued feedback, not only to teachers implementing change, but also to the facilitators and policy makers instrumental in the training of the teachers. This feedback, coupled with reflective practice, at all levels of the educational system provided the means for teachers to improve the success of all students in their classrooms. (Contains 1 figure and 1 table.)