The authors examined the reliability, sensitivity, and specificity of DSM-III and DSM-III-R criteria for autism in relation to each other and to clinical diagnoses in 114 children and adults (52 diagnosed by clinicians' best judgment as autistic and 62 as nonautistic but developmentally disordered). They used a standard, structured coding scheme to evaluate each patient. The reliability of specific criteria was generally high. Although DSM-III criteria were highly specific, they were less sensitive; the reverse was true for DSM-III-R. The authors conclude that the diagnostic concept of autism in DSM-III-R appears to have been substantially broadened.