Findings of a study that outlined the nature and scope of collaborative decision making between principals and teachers in Victoria, Australia, are presented in this paper. When the Cain Labor Government came to power in 1982, it mandated changes in education, including the use of site-based collaborative decision making. The Beginning Principals Study examined the ways in which beginning principals implemented the requirements for collaborative decision making in their schools. The longitudinal study, which began in 1989, involved a sample of eight and a sample of four first-time principals. Methodology included principal and teacher interviews, school visits, and a survey of principals. Findings suggest that the introduction of teachers' working conditions and staffing agreements and collaborative decision-making requirements have contributed to a reduction in industrial disputation, especially at the secondary school level. The collaborative decision-making model appeared to be generally well accepted and applied by beginning principals. However, practices varied by school and principal. Finally, principals and teachers generally lacked skills for effective shared decision making. (LMI)