To evaluate the approach to improving instruction espoused by the National Writing Project (NWP), this research report examines the assumptions, practices, and impacts of the NWP program to train teachers to teach writing. Following a brief description of the NWP model and its underlying assumptions, the report compares the goals, strategies, and achievements of the NWP with findings from recent research in adult development, effective in-service education and school change. The report concludes that (1) in the aim to change teacher attitudes and behaviors, and to create openness to change itself, the NWP is in consonance with adult development theorists, who value adaptive flexibility and cognitive complexity in a teacher; (2) as an in-service effort, the NWP succeeds in getting teachers to try new approaches and techniques, but fails to transfer these skills into teachers' active repertoires, presumably from lack of further reinforcement; and (3) in relation to school change, the NWP is deficient in implementing innovations in curriculum and instruction because its focus on teachers excludes administrator involvement, and because organizational barriers prevent teacher-consultants from institutionalizing new practices for writing instruction. The report recommends that the NWP include activities enhancing teacher consultancy to strengthen follow-up coaching, encourage administrator participation, and structure the school year in-service program so teachers may participate in the full series of activities. (JG)