A standardized tool for the observation and diagnosis of autism spectrum disorder (ASD), a structured assessment that includes a series of tasks and interactions between the clinician and the person who is suspected of having autism. ADOS evaluates communication, social interaction, play, and creative use of materials in a variety of contexts. This tool is designed for people of different age groups and developmental levels. ADOS helps assess both verbal and nonverbal behaviors and is often used in conjunction with other diagnostic techniques, such as the Autism Diagnostic Interview, Redesigned Version (ADI-R), for a more comprehensive diagnosis.