If you’re researching autism assessments, you may have come across the term ADOS, often described as “the gold standard” for diagnosing autism.
This can raise important questions:
- What is an ADOS assessment?
- Is an ADOS required for an autism diagnosis?
- Does ADOS work for adults as well as children?
- What actually happens during an ADOS assessment?
In this article, our Clinical Director, Jo Condon uses her extensive autism knowledge and experience to explain what ADOS is, how the ADOS is used and what to expect in an ADOS assessment.
What is the Autism Diagnostic Observation Schedule (ADOS)?
The Autism Diagnostic Observation Schedule (ADOS‑2) is a structured observational assessment used to observe social communication, interaction, play and behaviour associated with autism.
Rather than being a questionnaire or test with right or wrong answers, ADOS involves guided activities and conversations that allow a trained clinician to observe how someone communicates and interacts in real time.
The ADOS is a tool used as part of a complete autism assessment – it cannot provide a diagnosis on it’s own.
What happens during an ADOS assessment?
The ADOS assessment looks different depending on the individual’s age, language level and communication style.
During an ADOS session, a clinician may:
- Engage in conversation or shared activities
- Use structured activities or tasks
- Observe social reciprocity, communication style and non‑verbal cues
- Note sensory responses, imagination and flexibility
For children, the ADOS involves play‑based interaction. For adults, it involves more conversation and exploration of experiences.
The session is designed to feel supportive and respectful, and is not a test with right or wrong answers .
ADOS modules: why assessments are tailored
ADOS uses different modules, selected based on the person being assessed.
Some modules are designed for children who do not yet have complex speech, others are used for verbal children, adolescents or adults
In total, there are five different modules of the ADOS:
Toddler module: for children aged between 18 months and 30 months
Module 1: for those aged 31 months and over who are pre-verbal or are only using single words
Module 2: for those who are using phrased speech but are not verbally fluent
Module 3: for children aged under 10 who are verbally fluent
Module 4: for those aged 10 and over who are verbally fluent
Choosing the correct module is essential, which is why ADOS must be administered by a trained and experienced clinician.
Is ADOS the “gold standard” for autism diagnosis?
The ADOS is often described as a gold‑standard tool. This is because it has been widely tested and shown to be a valid, specific and reliable diagnostic assessment tool. As a semi-structured tool with specific training in administration, the test can be reliably replicated by different clinicians.
It is however important to understand that the ADOS 2 does not diagnose autism on its own.
A robust autism assessment also includes:
- A detailed developmental history
- Information from parents, partners or schools (where relevant)
- Clinical interviews
- Consideration of other conditions that may be present
At Jo Condon Autism Assessments, the ADOS is regularly used as part of our assessment process.
ADOS assessment for adolescents and adults
For fluent children aged around 10 or over, adolescents and adults, Module 4 of the ADOS is used. This module does not have play activities, and consists of tasks, questions and conversation.
The questions relate to the individual’s own experiences and views, and do not have right or wrong answers. The activities and questions in Module 4 offer further opportunities for the clinician to observe for characteristics of ASD such as:
· Difficulties with eye contact
· Reduced non-verbal communication
· Difficulties sustaining back-and-forth conversation
· Sensory issues
· Hand and finger mannerisms
· Highly specific interests
Understandably, some people feel quite anxious before their ADOS session, but there is no need to be. The ADOS is quite a light-touch assessment and is usually completed in under an hour.
ADOS for Older Children
For older children who are verbally fluent, up to around the age of 9 or 10, the ADOS module 3 is used, which consists of play activities, tasks and questions.
The assessment questions are focused on the child’s views and experiences, and the clinician will be interested in how the child shares these with them.
When administering the ADOS, the clinician will be observing for communication and interaction style, such as how the child:
· Uses non-verbal communication
· Uses language
· Responds to conversation cues
· Engages with social chit chat
· Plays
The clinician will also note any relevant behaviours such as:
· Intense interests
· Sensory interests
· Repetitive behaviours
ADOS assessment for younger children
For younger children who are not yet verbally fluent, the ADOS consists of play activities, and there are numerous toys to engage with.
During the session, the clinician will administer the different ADOS tasks and will observe the child’s responses and behaviours. Specific things that the ADOS administrator will be looking for include:
· How the child makes requests
· Whether they use non-verbal communication, such as gesture
· If they enjoy games and interaction with the clinician
· Sensory seeking or sensory avoidant behaviours
· Repetitive behaviours
There is no pressure for the child to engage, and the ADOS will be adapted if the child shows any sign of upset or distress
ADOS scores
After administering the session, the clinician will code the behaviours that they have or have not observed during the session. The behaviours that are coded are set out in the ADOS administration guidance. These codes are then converted into scores.
Behaviours are scored as 0, 1 or 2 depending on whether a particular behaviour was present or absent.
The ADOS assessment has an accompanying scoring algorithm. The relevant ADOS scores are added up using the algorithm, and the total scores are compared to the ADOS cut-off scores. This enables the clinician to see whether the assessment has identified behaviours that are consistent with an autism spectrum presentation.
If you choose an assessment with us, the ADOS scores will be documented in your report.
Final thoughts
The Autism Diagnostic Observation Schedule is a valuable assessment tool when used within a broader, professional clinical autism assessment piece of the puzzle.
A meaningful autism assessment looks at the whole person, across time, context and experience, not just what happens in one appointment.
This article has been written by our Clinical Director, Johanna Condon. Jo is a leading expert in autism and has contributed to the field of autism through published research, developing National guidance and advising public and private organisations. She completed her first autism assessment in 2002 and has 24 years experience across the NHS, national government and independent services. Her work is grounded in a neurodiversity-affirming, person-centred approach.
FAQ
Does ADOS work for adults?
The ADOS is widely used in adult autism assessments. Many autistic adults worry that their high-masking presentation will mean that signs of autism will not be observed during the ADOS, but this is rarely the case. Skilled ADOS administrators observe closely for the nuances of social interaction and can see masking and camouflaging behaviours.
The ADOS only forms part of the assessment and observed behaviours will be considered alongside other information gathered, including life experiences, thinking style and developmental history.
Is ADOS used for children?
Yes. ADOS is commonly used in child autism assessments. For children, the ADOS can help clinicians understand:
- Social communication style
- Play and imagination
- Response to interaction and change
Again, it is part of a multi‑source assessment, not a standalone decision.
Who developed the ADOS?
The ADOS was first developed in 1989 by Catherine Lord, Michael Rutter, Pamela DiLavore, and Susan Risi.
In 2012, ahead of the changes to the diagnostic criteria for autism, the Autism Diagnostic Observation Schedule – second edition, or ADOS-2, was published. The ADOS-2 is the version that is currently used for autism assessments.
Can the ADOS be completed online?
Research shows that the outcome of Module 4 ADOS is comparable whether completed in-person or online. There is no evidence to suggest that this is the same for any of the other ADOS modules. Therefore, children under 10 and individuals of any age who have not developed fluent speech will need to be seen in person.
Fluent individuals aged 10 or over can confidently choose to complete the assessment online if this is preferred.
How do I prepare for my ADOS assessment?
As an adult, the only preparation needed is in relation to accessing the session. Individuals may find it helpful to see the clinic and work out travel arrangements in advance to decrease anxiety around this on the day. If you are completing the ADOS online, you will be provided with instructions regarding setting this up. Remember, you will need a tablet or laptop as an ADOS cannot be completed via a phone.
How do I prepare my child for the ADOS assessment?
There is no specific preparation needed. You may wish to reassure your child that the session is about the clinician wanting to get to know them and that there are no right or wrong answers to any of the questions they might ask.
Your child may want to bring a familiar toy or object with them. The ADOS is usually completed in under an hour. It is best if your child does not bring food in with them, but they can bring a drink.
How long does the ADOS assessment take?
The ADOS administration time can vary depending on the individual being assessed. Usually, the ADOS takes between 40 and 60 minutes.
