Effectiveness
Findings
The WWC review of interventions for Early Childhood Education for Children with Disabilities addresses student outcomes in seven domains: cognitive development, communication and language competencies, literacy, math competencies, social-emotional development and behavior, functional abilities, and physical well-being. The studies included in this report cover four domains: cognitive development, communication/language competencies, social-emotional behavior and development, and functional abilities. The findings below present the authors’ estimates and WWC-calculated estimates of the size and the statistical significance of the effects of the Lovaas Model on children with disabilities.12
Cognitive development. Smith et al. (2000) reported a statistically significant difference on intellectual functioning favoring children in the intensive treatment group. According to the WWC calculations, this difference was not statistically significant, but the effect size was substantively important according to WWC criteria (that is, at least 0.25). According to the WWC criteria, the Lovaas Model has potentially positive effects on cognitive development for children with disabilities.
Communication/language competencies. Sallows and Graupner (2005) examined two outcomes. The authors found, and the WWC confirmed, that neither effect was statistically significant. Neither effect size was large enough to be considered substantively important according to WWC criteria. According to the WWC criteria, the Lovaas Model has no discernible effects on communication/language competencies for children with disabilities.
Social-emotional development and behavior. Sallows and Graupner (2005) examined three outcomes in this domain. Although none of the impacts in this domain were statistically significant, one finding was large enough to be considered substantively important according to WWC criteria. The mean effect size across all three outcomes was not large enough to be considered substantively important, and thus the WWC found the Lovaas Model to have no discernible effects on social-emotional development and behavior for children with disabilities.
Functional abilities. Sallows and Graupner (2005) examined one functional ability outcome. The authors found, and the WWC confirmed, that the effect was not statistically significant nor was the effect size large enough to be considered substantively important according to WWC criteria. Thus, the WWC concludes that the Lovaas Model has no discernible effects on functional abilities for children with disabilities.
Rating of effectiveness
The WWC rates the effects of an intervention in a given outcome domain as positive, potentially positive, mixed, no discernible effects, potentially negative, or negative. The rating of effectiveness takes into account four factors: the quality of the research design, the statistical significance of the findings, the size of the difference between participants in the intervention and the comparison conditions, and the consistency in findings across studies (see the WWC Procedures and Standards Handbook, Appendix E).
12 The level of statistical significance was reported by the study authors or, when necessary, calculated by the WWC to correct for clustering within classrooms or schools and for multiple comparisons. For the formulas the WWC used to calculate the statistical significance, see WWC Procedures and Standards Handbook, Appendix C for clustering and WWC Procedures and Standards Handbook, Appendix D for multiple comparisons. For the Lovaas Model studies summarized here, no corrections for clustering or multiple comparisons were needed. However, Smith et al. (2000) used a one-tailed test for the outcome data, whereas the WWC uses a two-tailed test, so the significance levels may differ from those reported in the original study.