The Autistic Diagnostic Observation Schedule (ADOS) is a semi-standardized test that can help diagnose developmental disorders such as autism. It is administered by a trained professional and can be useful for a variety of different ages and developmental levels. 

The ADOS test helps to assess communication, social, and imaginative skills using direct observation in a controlled environment and is one of the most popular standardized assessments used to help diagnose autism. 

What Is the Autistic Diagnostic Observation Schedule? 

Considered the gold standard for direct diagnostic assessment of autism, the current ADOS, the ADOS-2, uses prompts to track behaviors and social communication responses in a controlled environment observed by a trained professional. 

The ADOS can be administered by school counselors or personnel or independent clinicians who are professionally trained. Administrators of the ADOS must have a master’s or bachelor’s degree in a counseling or education field

The ADOS test is not necessary to diagnose autism as diagnostic criteria are set by the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders). But it can be a useful tool, especially when used in conjunction with other assessments and methods. The Autistic Diagnostic Observation Schedule is published by Western Psychological Services (WPS).

The ADOS uses standardized methods and materials to elicit responses to test communication, behaviors, verbal skills, physical actions, and interpersonal interactions. Autism is a developmental disorder that includes social and communication issues as well as repetitive behaviors and rigidity. The ADOS test can pinpoint these hallmarks of autism and scores their severity on a zero to three scale.

Modules of the ADOS Test

The ADOS has expanded the range of ages that can be tested since its initial inception in the 1980s. Originally, the Autistic Diagnostic Observation Schedule was intended to test children between the ages of 5 and 12 who had delays in expressive language skills. In 2000, the ADOS was modified, and its scope was expanded to include younger children and adults. In 2012, a second edition, the ADOS-2, was released that includes a toddler module for assessing children as young as 12 months.

The ADOS test includes four modules, as well as a fifth toddler module, and each is designed to test a different age and language level. The test itself takes between 30 and 60 minutes to complete. Only one module is used per person based on the developmental level and chronological age. 

The modules look like this:

  • Module 1. This module is typically used for young children who are not yet verbal or are nonverbal. It involves moving around the room and addresses nonverbal interactions and forms of communication. It can include free play, snacking, typical social interactions, and routines involving objects.
  • Module 2. Also intended for younger children, this module is for those who speak but are not yet verbally fluent. Like Module 1, the second module also involves moving around the room and interacting with objects. It uses make-believe play, book reading, conversations, and task demonstrations and constructions.
  • Module 3. This module is administered sitting at a table most of the time and is for children who are verbally fluent and play with age-appropriate toys. It includes some of the same components as Module 2, as well as cartoons, story creation, emotional analysis, social challenges, and communication reporting.
  • Module 4. Also administered mostly sitting down, this module is geared more toward older children — mostly adolescents — and adults who no longer play with toys. This module includes more real-life scenarios and discusses school or work, relationships, books, and future plans.

Using the ADOS & Additional Options

The ADOS is a diagnostic tool that can be helpful in diagnosing autism as well as determining its severity. It is best used as part of a multidisciplinary approach that can include other diagnostic tests and measures. The ADOS is an accurate tool for helping to diagnose children with autism; however, it can also produce false-positive results and should be used with care and in conjunction with other methods.

The Autism Diagnostic Interview-Revised (ADI-R) is often used in conjunction with the ADOS. Parents or caregivers fill out the ADI-R, and while results between the ADOS and ADI-R usually match up, parental influence can skew the data of the ADI-R and produce lower scores. Often parents or caregivers either do not recognize or find autistic traits problematic, which can account for this mismatch. This underscores the importance of having your child evaluated by a trained professional using a tool such as the ADOS.

Another diagnostic tool for autism is the Childhood Autism Ratings Scale (CARS), which was at one point misused as a questionnaire for parents and caregivers. It is intended to be administered by a trained clinician and can provide similar results as the ADOS when diagnosing autism. The CARS can help distinguish autism from other developmental disorders. 

The ADOS and other autism diagnostic tools are best performed by trained professionals who can work directly with parents to determine the presence of autism and then develop a treatment plan. 


The Promise of Telepractice to Address Functional and Behavioral Needs of Persons With Autism Spectrum Disorder. (2017). International Review of Research in Developmental Disabilities.

Qualification Guidelines. WPS.

Diagnostic and Statistical Manual of Mental Disorders (DSM-5). (2021). American Psychiatric Association (APA).  

(ADOS-2) Autism Diagnostic Observation Schedule, Second Edition. (2021). WPS.

The Autism Diagnostic Observation Schedule-Generic: A Standard Measure of Social and Communication Deficits Associated with the Spectrum of Autism. (June 2000). Journal of Autism and Developmental Disorders.

How Accurate Are Diagnostic Tools for Autism Spectrum Disorder in Preschool Children? (July 2016) Cochrane. 

Parental Concerns May Skew Scores on Autism Test. (August 2017). Spectrum News.

Childhood Autism Rating Scale, Second Edition (CARS2). (June 2020). CAR Autism Roadmap Children’s Hospital of Philadelphia.