First-year outcomes of the 1990-91 Project Achieve in 32 New York City public high schools are presented in this paper. The program aimed to reduce the dropout rate and improve at-risk student performance by expanding proven initiatives and support services for school-based decision-making committees. This report, the first of a two-part study, focuses on program implementation and the functioning of schoolwide committees. Methodology involved onsite observation and interviews with program coordinators, teachers, and students at 16 participating high schools. Findings indicate that coordinators responded positively to the schoolwide approach to decision making and program management. All sample schools expanded their houses program, developed new instructional initiatives, and instituted or expanded current options. Most schools broadened their community-based organization's services to at-risk students. All participating schools either elected an inclusive shared decision-making committee or utilized an existing school-based management/decision-making committee. Many schoolwide committees changed traditional class schedules, which facilitated innovative instructional initiatives. Recommendations are made to create smaller professional inservice workshops, provide a central clearinghouse to coordinate technical assistance, continue to support successful initiatives, and develop a comprehensive research project. Six tables are included. The appendix lists participating high schools for 1990-91. (LMI)