This proposal will result in the development of a new screening instrument to identify children with autism spectrum disorders (ASD). Several investigations are currently underway in order to better understand the causes of ASD. Many of these studies require very large numbers of participants; however, current methods for identifying participants for such studies are often expensive and time-consuming and require intensive training. To address these issues, this project will create a short parent interview that can be administered on the telephone to quickly identify potential participants for ASD research. This new instrument will facilitate research into ASD etiology by increasing the speed and effectiveness of participant recruitment efforts. In addition, such an instrument may have other practical uses clinically. In communities where the wait for an ASD evaluation is extremely long or there are no local resources for diagnostic evaluations, an efficient screening instrument that could be administered by phone might help triage children in need of further evaluation and/or be used to qualify children for certain intervention services pending a more complete diagnostic evaluation at a later time.