The Training of Trainers (ToT) Evaluation investigated the efficacy of the High/Scope model for improving the quality of early childhood programs on a national scale. To address this question, the High/Scope Foundation undertook a multimethod evaluation that collected anecdotal records from the consultants and 793 participants in 40 ToT projects, surveyed a random sample of 203 endorsed trainers around the country, interviewed and observed highly qualified teachers in 244 High/Scope and 122 non-High/Scope settings, and assessed 97 children in High/Scope and 103 in comparison programs. In addition to the particular question about High/Scope's effectiveness in doing training, the study also addressed broader questions about the role of inservice training in improving early childhood program quality and enhancing young children's development. Some of the results of the study include the following: (1) High/Scope training is effective, and evidence indicated that inservice training contributes significantly to program quality and children's development; (2) although both High/Scope and comparison settings offered high-quality programs, there were significant differences. High/Scope programs were better than comparison programs at organizing the environment, encouraging independent thought and action, and using adult-child interaction to promote reasoning and language skills; (3) teachers' formal education, inservice training, and experience were all significant predictors of program quality. Contains 56 references. (TJQ)