| Abstract: | This study investigated the validity of the Autism Behavior Checklist (ABC; Krug, Arick, & Almond, 1993) and the Pervasive Developmental Disorders Rating Scale (PDDRS; Eaves, 1993a). Both instruments are screening devices designed to measure characteristics of individuals with autistic disorder or, more broadly, pervasive developmental disorders. Results showed that the total scores of the ABC and PDDRS measure significantly overlapping constructs (r= .80). Further, both instruments significantly discriminated between participants with autistic disorder and children with diagnoses frequently confused with autistic disorder. Both instruments provided respectable indices for classification accuracy (PDDRS overall accuracy = 88%, ABC overall accuracy = 80%). Finally, the ABC and PDDRS agreed in their classifications of 85% of the 136 participants; a phi coefficient based on the instruments' nominal classifications of the participants equaled .68 (p< .001). © 2000 John Wiley & Sons, Inc. |
