An integrative review of early intervention efficacy studies with at-risk children: Implications for the handicapped

Results of 162 early intervention efficacy studies with disadvantaged, at-risk, and handicapped children were analyzed to draw conclusions about the efficacy of early intervention, identify variables which covary with effectiveness, and identify areas for future research. Because of the scarcity of data and methodological problems with efficacy studies with handicapped children, much of the paper focuses on conclusions drawn from research with disadvantaged and at-risk populations and the implications of those data for handicapped children. It is concluded that early intervention has substantial immediate benefits for at-risk and disadvantaged children. What few data are available about the effects of parental involvement, age at which intervention starts, training of the intervenor, and maintenance of effects are often contrary to what many people have assumed. Methodological suggestions to improve future early intervention research are discussed.