diagnosis of autism, even though there are strong and consistent commonalities, especially relative to social deficits.

The large constellation of behaviors that define autistic spectrum disorders—generally representing deficits in social interaction, verbal and nonverbal communication, and restricted patterns of interest or behaviors—are clearly and reliably identifiable in very young children to experienced clinicians and educators. However, distinctions among classical autism and atypical autism, pervasive developmental disorder-not otherwise specified (PDD-NOS), and Asperger’s disorder can be arbitrary and are often associated with the presence or severity of handicaps, such as mental retardation and severe language impairment.

Identifying narrow categories within autism is necessary for some research purposes; however, the clinical or educational benefit to subclassifying autistic spectrum disorders purely by diagnosis is debated. In contrast, individual differences in language development, verbal and nonverbal communication, sensory or motor skills, adaptive behavior, and cognitive abilities have significant effects on behavioral presentation and outcome, and, consequently, have specific implications for educational goals and strategies. Thus, the most important considerations in programming have to do with the strengths and weaknesses of the individual child, the age at diagnosis, and early intervention.

With adequate time and training, the diagnosis of autistic spectrum disorders can be made reliably in 2-year-olds by professionals experienced in the diagnostic assessment of young children with autistic spectrum disorders. Many families report becoming concerned about their children’s behavior and expressing this concern, usually to health professionals, even before this time. Research is under way to develop reliable methods of identification for even younger ages. Children with autistic spectrum disorders, like children with vision or hearing problems, require early identification and diagnosis to equip them with the skills (e.g., imitation, communication) to benefit from educational services, with some evidence that earlier initiation of specific services for autistic spectrum disorders is associated with greater response to treatment. Thus, well meaning attempts not to label children with formal diagnoses can deprive children of specialized services. There are clear reasons for early identification of children, even as young as two years of age, within the autism spectrum.

Epidemiological studies and service-based reports indicate that the prevalence of autistic spectrum disorders has increased in the last 10 years, in part due to better identification and broader categorization by educators, physicians, and other professionals. There is little doubt that more children are being identified as requiring specific educational interventions for autistic spectrum disorders. This has implications for the provision of services at many levels. Analysis of data from the Office of