The paper discusses programs established to assist in the development of handicapped and "at risk" children, with particular interest on the structures of the different programs, the methods of investigating program impact, and the findings of these studies. Following a review of historical bases of early intervention, the author looks at programs which include the Early Training Project (Nashville, Tennessee), the Perry Preschool Project (Ypsilanti, Michigan), and the Sheltering Arms Day School. Among the methods mentioned for studying program impact are pretest-posttest control group design, the secular trend methodology, and the theoretical control group study. Results of previous investigations and variables associated with program success are listed. Detailed is the methodology for a proposed longitudinal study investigating social, physical, and cognitive variables in child progress during intervention through Project KIDS, a program providing training services to parents in addition to children's services. (SB)