There is a need for well-controlled clinical outcome research on these and other models of service delivery. The available research strongly suggests that a substantial subset of children with autistic spectrum disorders are able to make marked progress during the period that they receive intensive early intervention, and nearly all children with autistic spectrum disorders appear to show some benefit. However, the research to date is not at a level of experimental sophistication that permits unequivocal statements on the efficacy of a given approach, nor do the data support claims of “recovery” from autistic spectrum disorders as a function of early intervention. There is no outcome study published in a peer-reviewed journal that supports comparative statements of the superiority of one model or approach over another. Rather, with a few exceptions, much of the current outcome information is in the form of program evaluation data or measures of children’s progress when comparisons are made before and after intervention without control groups or blinded assessments of outcome. Although many children have participated in the ten model programs, outcome data is generally based on small samples, and the small sample size has also prohibited analysis of the role of individual differences within children in the effectiveness of different models.
The components of the ten program models discussed above are empirically grounded. Researchers working with each of them have published numerous peer-reviewed findings specific to the procedures developed in their programs, although the level of standards for intervention studies varies considerably across journals. In some cases, the programs originated as applied laboratories in which to develop and test intervention procedures, so research about the effects of specific procedures was the natural output. As reviewed in other sections of this report, this cumulative body of procedural research serves as evidence that early educational interventions do enable young children with autistic spectrum disorders to acquire a variety of skills.
However, the quality and quantity of research that evaluates the overall efficacy of these models has lagged behind the procedural research. The paucity of outcome data may be due to the fact that early education programs for children with autistic spectrum disorders are relatively new. The ethical and logistical complexity of conducting clinical outcome research with young children is also a major contributing factor.
Examples of the outcome data generated by the ten selected models to date are presented in this section; the models are covered in alphabetical order. The studies discussed were published in peer-reviewed journals; these journals vary widely in the experimental rigor of their review process. In several cases, published data were provided to augment program description information rather than as results of experimental tests.