One measure of a scholar's contributions to his field is the extent to which his work has impact beyond his area or original focus. The authors' examine N. L. Gage's impact in the area of school effects research. The first of Gage's impacts has been in arguing for a pragmatic orientation to the building of a scientific base for the study of education. The second has been in both leading and supporting studies that focused on direct observation of classroom teaching processes, and linking those processes to measurable outcomes. Four examples of the impacts of Gage's work are presented and discussed. The school effects field would not have made as much progress had not the teacher effects field generally, and the work of N. L. Gage in particular, preceded it.