The primary goal of the School Improvement Project (SIP), administered by the central office of New York City (New York) Public Schools, is to improve academic achievement through school-based planning. A planning committee representing the various school constituencies is responsible for developing and implementing a comprehensive plan to effect changes in administrative style, basic skills instruction, school climate, student assessment, and teacher expectations. During successive years in the project, schools are encouraged to depend less on project direction and support, and to become increasingly self-sustaining. During 1983-84 the Project's goals were the following: (1) to implement improvement plans in 13 second-year ("D") schools; (2) to begin independent institutionalization of improvement planning in four third-year ("C") schools; (3) to maintain institutionalization in eight fourth-year ("B") and four fifth-year ("A") schools; and (4) to continue training project and school staff. After five years of Project implementation, some patterns have begun to emerge identifying school factors that promote or impede success. The most critical factor has been the principal's commitment and backing. Strong, effective committees and school-wide cooperation are also critical factors. Principals, chairpersons, and committees seem to have come to a consensus regarding the definition of school improvement success or failure and their own investment in the process. That the principal can accept and support constituency planning without being threatened by it is a critical criterion. (Author/BJV)