This study is based on an external assessment of the School Self-Renewal Program in New York City. The program represents the largest and longest running Organization Development (OD) program in the country. Twelve of 24 high schools participating in the program in 1977 were sampled. The renewal model employed for school based change was found to be a powerful influence on the participative problem solving process. It proved to be flexible in its successful application in a variety of subsystems: school wide staff groups, student groups, administrative teams, and academic departments. In addition, a number of improvements were found to have occurred in the areas of curriculum, administrative reorganization, and mini-schools. The role of the OD consultant team in bringing about these improvements, processes by which the program is funded, and the current status of the program are described in this document. The limitations of OD as a process for improvement of urban secondary schools are also analyzed. (Author/GC)