The Collaborative School Improvement Process (C-SIP) is a six-step process based on participative decision making and staff development. The identification of participants' perceptions of the program and reasons for variation is the purpose of this study. Data collection is based on a survey of teachers and administrators in 29 participating schools. The return rate and total number of respondents are not stated. With the exception of two schools, findings indicate that the majority of participants perceived the C-CIP process as effective. Reasons for program effectiveness include: shared decision making and goal consensus; active involvement that meets basic human needs; well-organized planning; adequate funding; and utilization of a process facilitator. Recommendations are offered for improving time management, staff commitment, and evaluation. Appendices include a funding statement, a copy of the questionnaire, and tables of responses by school and by group. (LMI)