Although several of these literatures appear to be internally well integrated, there is remarkably little integration across literatures. For example, the information from the literature describing characteristics of children with autistic spectrum disorders is often not linked to treatment programs. Likewise, the developmental literature, which is descriptive in nature, has only rarely been integrated into individual intervention practice research, which tends to be behaviorally oriented (see Lifter et al., 1993 for a notable exception). Similarly, research that emphasizes the relationships among behaviors in response to treatment has been much more rare than descriptive studies of development in multiple domains (Wolery and Garfinkle, 2000).

Integration of the collective body of knowledge represented in these four literatures is important and could inform practice. It would be productive for leaders from these four research traditions to communicate regularly around the common issue of educational interventions for young children with autistic spectrum disorders. This communication could foster the research integration that appears to be missing from the literature. Communication could be enhanced by a series of meetings that bring together researchers and agencies who sponsor research, focusing on the task of reporting implications for designing programs for young children with autistic spectrum disorders.

One assumption in early intervention research is that treatment should begin as soon as possible. However, to accomplish this, children must be identified. Early diagnosis has important implications for treatment, since different interventions would be appropriate for very young children (e.g., 15 months of age) than for children of 2 or 3 years old.

There is a difference between screening and diagnosis. Screening, as understood in the United States, may mean two things. One is a process carried out by a primary care provider to decide whether a referral for more services is warranted: for example, a pediatrician, told by parents that their 18-month old child has poor eye contact and has stopped speaking within the last month, must decide whether and where to refer the child for further assessment. A second type of screening is a public health process by which health care providers routinely assess for risk for autistic spectrum disorders in children whose parents have not necessarily raised concerns.

Diagnosis is a much more comprehensive process carried out by a specialized team of professionals. For autistic spectrum disorders, diagnosis involves not only identifying the disorder and any other developmental and behavioral disorders associated with it, but also helping parents to understand the meaning of the diagnostic terms and what the