The Autism Diagnostic Observation Schedule (ADOS) is an essential piece of the autism diagnosis puzzle. Originally developed by American psychologist Catherine Lord (PhD) and her colleagues, a revised edition was published in 2012 and is referred to as the ADOS-2.
The ADOS-2 is a semi-structured, standardized observational tool used by licensed clinicians to evaluate autism spectrum disorder. It is described as “semi-structured” because, while the activities are standardized, clinicians are allowed to be somewhat flexible in their sequencing and delivery, depending on the child and the setting. The ADOS-2 is administered by trained clinicians, typically licensed psychologists, neuropsychologists, or developmental-behavioral pediatricians who have completed a formal ADOS-2 training workshop.
This is not a pass/fail assessment. When the assessment is complete, the results fall into one of three classifications: autism, autism spectrum, or non-autism. If a diagnosis is confirmed, ART utilizes the information gleaned from the ADOS-2 and other diagnostic tools to inform your child’s ABA therapy plan.
In most cases, a child’s ASD diagnosis is the culmination of:
It’s important to note that no child should receive a diagnosis of autism spectrum disorder (ASD) from a single exam or screening. Accurate diagnosis, which leads to best-practice early interventions, relies on experienced professionals and standardized procedures.
The results from the ADOS-2, combined with information gathered via other screenings, observations, and historical observations, culminate in determining whether or not a child has ASD. If the diagnosis is positive, these various screening and assessment tools also provide information about a child’s ASD Level. They are imperative in creating a personalized therapeutic intervention and support plan.
Only trained, licensed clinicians can legally administer the ADOS-2. In addition to formal ADOS-2 training, the minimum qualifications are a master’s degree in:
As a result, the person performing the ADOS-2 is most likely to be a:
During the age-specific evaluation, the clinician observes four domains: social interaction, communication, play skills, and restricted or repetitive behaviors.
These four domains are evaluated according to five separate, age-specific modules (see below):
Keeping the assessed individual’s age in mind, administering clinicians use standard scenarios, in a semi-structured format, to observe:
Each of the various standardized play scenarios is called a “Press”. And again, while the presses themselves are standard, the test’s format is considered semi-structured, rather than a formal, sit-down test. The clinician has some leeway to set up typical play scenarios and then interact with the child to observe their responses and behaviors as they naturally unfold. The goal is never to antagonize or trigger a child.
The duration of the ADOS-2 is usually between 40 and 60 minutes. It is a much more in-depth, observational evaluation, rather than a quick questionnaire or screening tool like the M-CHAT.
There are five ADOS-2 modules, and clinicians choose specific modules that best align with a child’s age and verbal ability.
| Module | Who It's For | Language Level |
|---|---|---|
| Toddler (T) | 12-30 months | No consistent phrase speech |
| Module 1 | 31+ months or older nonverbal | No consistent phrase speech |
| Module 2 | Any age | Some phrase speech, not fluent |
| Module 3 | Children and adolescents | Verbally fluent |
| Module 4 | Adolescents and adults | Verbally fluent |
The clinician selects a module based on the child's age and current language level, not on the severity of the suspected autism. So, if your child’s assessing clinician tests on Module 3 rather than Module 2, this does not indicate that they “might be more autistic” than if they were assessed using the lower module.
Module T (Toddler Module) is unique among the other. This is because the range of verbal, emotional, and skills is highly variable from child to child during this phase in early childhood development. For this reason, when a child is between 12 and 30 months, the ADOS-2 Toddler Module does not produce a diagnostic classification. Instead, it yields ranges of concern with regard to an ASD diagnosis: little-to-no, mild-to-moderate, or moderate-to-severe.
Here is what you can expect during your child’s ADOS-2 evaluation, keeping in mind that this semi-structured assessment should feel like lighthearted, structured play rather than a serious or clinical exam. If the child is old enough to understand, the clinician will communicate something like, “We are excited to play with you so you don’t have to worry about being tested or formally evaluated.”
During the session, your child may be excited to see some of their favorite types of toys, books, games, or other age-appropriate materials the clinician has in the assessment area. All of the activities are designed for the child’s developmental level.
The clinician will then use these materials to set up scenarios that allow for accurate observation. This may be looking at pictures and describing what’s happening or how the characters might feel. Or there may be a pretend meal to eat, cars to play with, dolls to dress, and games to play together.
Throughout the process, the clinician observes how the child spontaneously:
Depending on the age or comfort level of the child, parents are usually present with the child and clinician, or they’re in an adjacent observation room. This varies from clinic to clinic.
While the clinician-child portion of the ADOS-2 assessment takes between 40 and 60 minutes, there may be additional parent/caregiver interviews and other assessments that add more time to the overall process, or future appointments.
Rest assured, however, that this process is not designed to be stressful for your child - or you - in any way. Quite the opposite. The goal is to create everyday conditions where a child’s natural behavior can emerge.
You are bound to come across a number of unfamiliar autism-related words or phrases when you read your child’s ADOS-2 results to determine how they are scored. This can feel overwhelming, so we recommend having a guide of common autism terms handy to help you along the way.
Just some reminders to prevent misconceptions about ADOS 2 assessments and ASD diagnoses:
If your child is between the ages of 31-months through adolescence (Modules 1 - 3), you’ll also receive a comparison score. This score compares their symptom profile with other peers of their same age group and language level who have ASD diagnoses. Scores are NOT severity ratings nor do they map to DSM-5 autism levels 1, 2, or 3.
Just as an autism range result doesn’t automatically mean your child has an autism diagnosis, a “non-spectrum” result does not automatically rule out ASD if other clinical assessments or information indicate otherwise.
The scores of a stand-alone ADOS-2 assessment are not considered an official diagnosis because they are part of the broader diagnostic process.
The current “gold standard” of ASD diagnosis combines what the clinician observes (ADOS-2) and what the parent reports about the child’s developmental history (ADI-R). As we mentioned above, a formal autism diagnosis requires multiple pieces of a full puzzle, including:
That said, the ADOS-2 assessment remains the most rigorously validated observational tool, with high accuracy in both statistical sensitivity and specificity.
Of course, the quality of the assessment scores directly correlates with the clinician's expertise. Your child’s assessment is best performed by an ADOS-trained and experienced psychologist, neuropsychologist, or developmental pediatrician.
After the evaluation is complete, the diagnosing clinician issues a written report summarizing their findings. When applicable, this might also include an official ASD diagnosis. In most cases, parents or primary caregivers receive results at a feedback session, facilitated by the evaluating clinician.
According to the NIH, Current research shows that early diagnosis of and interventions for autism are more likely to have major long-term positive effects on symptoms and later skills.” For that reason, we recommend taking a proactive and multi-faceted approach to transforming the results of the ADOS-2 and all other assessment/testing data and assembling your child’s support team.
This includes sharing results with:
Here in North Texas, ABA therapy is typically one of the first interventions recommended after diagnosis. ART offers ABA therapy services to families starting at this stage, including work with toddlers who haven’t yet entered the school system.
If your child has recently received an autism diagnosis, ART's team is ready to help. We provide individualized ABA therapy across five North Texas locations, and we work closely with families from the first conversation. Contact us online for a free consultation, or call us at (877) 772-7889 to learn more about how ABA therapy sets children with ASD and their families on the road to success.
