The problem of this study is the effect of two training models on personnel who teach moderately and severely retarded children. The subjects of this study were sixty-two staff members who work with the moderately and severely retarded pupils in two large metropolitan school systems. Eighteen teachers, eighteen aides, and twenty-six volunteers participated in the study. Two observation instruments administered by trained observers were used as pre- and post-tests to measure the trainees' competencies in applying operant conditioning techniques in both group and one-to-one instructional situations. The purposes of this study were (1) to compare the effectiveness of an experiential model and a didactic model in preparing personnel to deliver cues and reinforcers when working with moderately and severely retarded children; (2) to compare the costs of equipment and supervisory personnel; and (3) to examine the relationship between the trainees' effectiveness of delivering cues and reinforcers to a group of moderately and severely retarded youngsters and the on-task behavior of those students. This report concludes that the trainees' self-evaluation of the training models indicated that they prefer simulated techniques and feedback, which denotes that the Experiential Model may foster certain kinds of incidental learning such as physical mannerisms and visual …