Arguments presented in this paper and the evidence from the Tasmanian Successful School Principals Project support broadening "what" counts for successful schools and school leadership. This broadening needs to embrace student outcomes, including non-cognitive social outcomes such as student empowerment. In examining who should provide the evidence for successful school leadership the need for triangulation, that is, multiple sources of evidence, became clear. Research employing only principal perceptions of success, especially on the importance of and improvement in student outcomes, should be examined much more critically than has occurred in the past. (Contains 5 tables and 7 figures.)