While school-based management (SBM) is increasingly becoming a part of state and district reform efforts, there is little evidence that it improves school performance. However, this may be an unrealistic expectation for a governance-oriented reform. SBM also can improve organizational performance not only when people at lower levels are brought into the decision-making process, but when these people are trained for their new roles and rewarded for achievement. This study examined whether and under what conditions high-involvement SBM, when combined with curriculum and instruction reforms, could improve school performance. Twenty-four schools in four North American school districts were studied using interviews and surveys. The results supported the importance of three elements in SBM: knowledge and skills training for those involved; access to information about the performance of the organization; and rewards granted for results. These findings contribute to a new understanding of SBM that goes beyond the traditional boundaries of mechanisms for sharing power. Also, to improve school performance, SBM must focus school-level educators' attention on performance rather than new management structures. (Contains 29 references.) (JPT)