To improve secondary school organization, operation, and outcomes, a research report presents major results from 13 studies of leadership, decision-making, and change conducted by Project on the Administration and Organization for Instruction staff at the University of Wisconsin-Madison in cooperation with over 100 schools. National and statewide professional eduational associations, institutions, and agencies nominated innovative and effective schools for the studies. Five studies focused on hypothesis testing of a priori theory utilizing rationalistic, quantitative approaches; eight studies utilized naturalistic, qualitative techniques, including interviews, observations, and record analysis by multiple researchers. All data were gathered on site. Results show that principals, the key educational leaders within schools, achieve positive outcomes by balancing structural/facilitative and supportive/participative behavior. Analysis shows that the content of the issue to be decided determines who is involved and to what extent, before, during, and after a decision is made. Seven change phases reveal the interaction of leadership, decision-making, and change: germination, initiation, evaluation, implementation, routinization, refinement, and renewal. Although oversimplified, these phases describe the interrelationships of leaders and staff in implementing planned educational change for school effectiveness. (PB)