This article describes the results of a series of studies that involved functional communication training (FCT) conducted in children's homes by their parents. The 103 children who participated were six years old or younger, had developmental delays, and engaged in destructive behaviors such as self-injury. The core procedures used in each study were functional analyses (FA) and FCT conducted by parents with coaching by the investigators. The overall results of the projects showed that the FA plus FCT intervention package produced substantial reductions in destructive behavior (M = 90%), which were often maintained following treatment. In terms of behavioral momentum theory, these results suggest that analyses of behavioral persistence provide an explicit technology of maintenance.