Staff development in cooperative learning must focus on three stages of staff development (pre-training, training, and post-training) to achieve at least five purposes. The five purposes are: creating conditions for successful staff development prior to training; conducting high-quality training sessions that result in mastery of the conceptual framework and procedures for using cooperative learning; providing support for the transfer of what is learned in the sessions to the classroom; providing support for the long-term maintenance of the learned procedures; and institutionalization of cooperative learning as a standard instructional practice supported by the district. To achieve the five purposes, eight principles of staff development must be followed: (1) establish long-term goals; (2) avoid the barriers to effective staff development; (3) create collegial teaching teams as the heart of staff development efforts; (4) plan multi-year staff development programs; (5) follow the guidelines for effective preparation for staff development sessions; (6) practice what one teaches in staff development sessions (use cooperative procedures); (7) support implementation between and after training sessions; and (8) change the school's organizational structure from a mass production structure to a team-based, high-performance structure. (Contains 58 references.) (SM)