As part of the Study of Dissemination Efforts Supporting School Improvement, researchers looked at how the activities of, perceptions of, and opinions about the building administrator affect the outcome of efforts to implement new practices. This paper describes a sample of building administrators working in the 146 school districts that participated in the study. It characterizes the forms of assistance provided by administrators to staff members implementing new practices, identifies the long-term strategies established for maintaining new practices, and summarizes the general roles played by school administrators in encouraging school improvement. Individually-focused and school-focused models of school improvement, developed during the study, are drawn on to clarify the effect of building administrators on improvement efforts at both the teacher and building levels. (Author/PGD)