Research
Fifty-eight studies reviewed by the WWC investigated the effects of the Lovaas Model on children with disabilities. One study (Sallows & Graupner, 2005) is a randomized controlled trial that meets WWC evidence standards. One study (Smith, Groen, & Wynn, 2000) is a randomized controlled trial with severe attrition that meets WWC evidence standards with reservations. The remaining 56 studies do not meet either WWC evidence standards or eligibility screens.
Meets evidence standards
Sallows and Graupner (2005) randomly assigned students to receive the Lovaas Model with a trained therapist or a parent-directed treatment using the Lovaas methods. Twenty-three children participated in the study, which examined cognitive development, communication and language competencies, social-emotional development and behavior, and functional abilities.10
Meets evidence standards with reservations
The study by Smith et al. (2000) was conducted in the Los Angeles area with 28 children with autism or a pervasive developmental disorder not otherwise specified. The study compared the cognitive development of children in the treatment group, who received 30 hours per week of the Lovaas Model with trained student therapists, to children in the parent-training group, whose parents were taught the same methods used in the Lovaas Model.10
Extent of evidence
The WWC categorizes the extent of evidence in each domain as small or medium to large (see the WWC Procedures and Standards Handbook, Appendix G). The extent of evidence takes into account the number of studies and the total sample size across the studies that meet WWC evidence standards with or without reservations.11
The WWC considers the extent of evidence for the Lovaas Model on children with disabilities to be small for cognitive development, communication/language competencies, social-emotional development and behavior, and functional abilities. No studies that meet WWC evidence standards with or without reservations examined the effectiveness of the Lovaas Model on children with disabilities in the literacy, math competencies, or physical well-being domains.
10 The study included other outcomes, which are excluded from this report because baseline equivalence was not established or required the use of adjustments, or the outcomes did not meet the topic area criteria for acceptable outcomes.
11 The extent of evidence categorization was developed to tell readers how much evidence was used to determine the intervention rating, focusing on the number and size of studies. Additional factors associated with a related concept—external validity, such as the students’ demographics and the types of settings in which studies took place—are not taken into account for the categorization. Information about how the extent of evidence rating was determined for the Lovaas Model is in Appendix A5.