Analysis and Intervention in Developmental Disabilities, Vol. 5, pp. 59-71, 1985 0270-4684/85 $3.00+ .00 Printed in the USA. All rights reserved. Copyright © 1985 Pergamon Press Ltd. Behavior Engagement as a Measure of the Efficacy of Early Intervention R. A. McWilliam Carol M. Trivette Carl I. Dunst Western Carolina Center This study investigated the usefulness of behavior engagement as an outcome measure for discerning the efficacy of intervention efforts, broadly conceived a~, specific attempts at affecting child performance through environmental manipula- tion. Engagement refers to the amount of time children spend interacting with the environment in a developmentally appropriate manner. Levels o f engagement were measured using the Planned Activity Check (PLA-Check) among preschool men- tally retarded, handicapped, at-risk, and nonhandicapped children participating in two different types of programs. One was traditional in orientation and the other nontraditional. The traditional program focused on the children manifesting discrete forms of criterion behavior, while the nontraditional program emphasized engagement as the focus of classroom efforts. PLA-Checks were taken during four classroom activities on 2 separate days. The results showed the engagement levels differed as a function of program type and classroom activities within programs. Engagement levels werefound to be consistently more stable in the nontraditional program. The findings were discussed in terms of the usefulness of engagement as a behavioral measure of the efficacy of early intervention. The purpose of this study was to investigate the usefulness of behavior engage- ment as an index of children's performance in discerning the efficacy of ear- Reprints may be obtained from R. A. MeWilliam, Family, Infant and Preschool Program, Western Carolina Center, Morganton, N.C. 28655. Work reported in this paper was supported in part, by a grant from the U.S. Department of Education, Office of Special Education Programs (1 #G008302292). Appreciation is extended to Olivia Carswell for help in preparation of the manuscript, Johnna Clontz and Nancy Johnson for assistance in data collection and analysis, and the staff, parents, and children at the preschool programs that participated in this study for their cooperation. 59