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Autism Diagnostic Observation Schedule (ADOS-2)
12 months through adulthood
The Autism Diagnostic Observation Schedule, Second Edition, is a structured observational assessment used within autism assessments. It is often described as the reference standard observational measure, and it is also searched for as the ADOS-2 test and the ADOS assessment.
It creates situations in which social communication and interaction can be observed directly rather than only reported on. It is never used alone.
How does the ADOS-2 work?
The ADOS-2 has five modules. The psychologist selects one based on age and expressive language level, ranging from a toddler module for young children with little or no speech through to Module 4 for verbally fluent adolescents and adults.
Each module presents structured activities and conversational prompts designed to create natural opportunities for social interaction. For younger children these are play-based. For adults the session looks much more like a conversation, covering friendships, work, emotions and everyday social situations.
The psychologist codes specific behaviours as they occur and converts these into an algorithm score. That score is one input into a clinical judgement, not a verdict.
What are the limits of the ADOS-2?
It is a snapshot of one session in an unfamiliar room with an unfamiliar person, and that matters in both directions.
People who have learned to mask, which is more common in autistic women and in adults assessed later in life, can score below threshold while still meeting diagnostic criteria on the full picture. Conversely, anxiety, trauma, language difference or intellectual disability can produce presentations that score above threshold without autism being the best explanation.
This is why a responsible assessment never rests on the ADOS-2 alone, and why developmental history and information from people who know the person well carry substantial weight.
What else is part of an autism assessment?
A detailed developmental history taken from a parent or caregiver where available, standardised questionnaires completed by the person and by those who know them, information from school or workplace where relevant, consideration of alternative and co-occurring explanations, and direct clinical observation.
Diagnosis is made against DSM-5-TR criteria by the clinician, weighing all of it together.
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This page is general information about an assessment instrument and is not clinical advice. Whether a particular assessment is appropriate depends on the individual and the question being asked.