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What is the Autistic Diagnostic Observation Schedule (ADOS)?

September 29, 2023

So, the time has come to finally find out if your child is indeed autistic. Maybe you have waited for months for this appointment. Nerves may threaten to get the best of you, but you are strong. Get ready, your life is about to change, and it’s going to be a wild ride.

What is the Autistic Diagnostic Observation Schedule (ADOS)?

Breathe, you’ve got this! The first step on this incredible journey to receiving help for your child is taken here. The doctor welcomes you into their office, “We will begin with the autistic diagnostic observation schedule…”

The words “autism diagnostic observation schedule (ADOS)” may elicit some anxiety, especially if you have never heard of it, or don’t know what it is. In this article I would like to offer some comfort by way of explaining what an ADOS is, how it works, and who is qualified to administer one. Keep in mind that, as overwhelming as it sounds, it really will go a long way to helping your child.

What is an autism diagnostic observation schedule?

An autism diagnostic observation schedule is a standardized assessment used to diagnose autism. The ADOS is just one part of a full comprehensive evaluation.

The ADOS was developed to be a way to take the commonality that exists between autism cases and come up with a standard of measurement. This measurement allows for variations while giving a guideline for professionals who are attempting to determine an autism diagnosis.

Along with the diagnosis, other criteria are identified that help parents and professionals understand where on the spectrum an individual may be, and what the next steps would be to get them the support they need.

How does the ADOS work?

After the initial autism evaluation, a patient will likely be referred for an autism diagnostic observation schedule if they are suspected to be on the autism spectrum.

According to a study published on the National Library of Medicine’s website: The Autism Diagnostic Observation Schedule-Generic (ADOS-G) is a semi structured, standardized assessment of social interaction, communication, play, and imaginative use of materials for individuals suspected of having autism spectrum disorders. The observational schedule consists of four 30-minute modules, each designed to be administered to different individuals according to their level of expressive language.”

While monitoring the patient, a professional will ask the child to engage in several activities. How they manage each task is observed, and the information is documented and assessed. 

These tasks can include:

  • building with blocks or other materials
  • engaging in conversation
  • telling a story from a book
  • transitioning from activities
  • using their imagination

Through this standardized assessment a patient’s social interaction and language skills are tested to help determine their educational placement, and what therapies, support, or accommodations may benefit them.

They will observe while the child plays and engages with others while they complete the tasks and activities provided to them. If they exhibit traits that align with criteria for an autism diagnosis or not will be noted. These traits include but are not limited to:

  • repetitive behaviors
  • lack of eye contact
  • delayed speech
  • lack of social interaction
  • rigid thinking

If not, the information is used to help the parent understand if their child may have other challenges, or if the child is not believed to be on the autism spectrum.

The ADOS will allow the professional to form clinical impressions about the developmental level of the patient. It will help answer some questions:

  • Is the child able to perform tasks on par with their chronological age?
  • What is the expressive language level of the child; are they verbally fluent and do they have similar language skills as their peers?
  • How do they interact with others?
  • Do they play well by themselves?
  • What is their coordination like?
  • How is their emotional regulation?
  • How do they handle transitioning from one thing to another?

Answering these questions and more is an integral part of the process. When the ADOS is complete, the information gathered is shared with the parents. If a diagnosis for autism is appropriate and given, the patient can move forward with treatment planning.

Sometimes children’s behavior can be drastically altered by the presence of a parent. Depending on the age of the child, parents may be encouraged to be present. Many times, however, this is not the case.

What is the history of the ADOS?

The diagnosis of autism is much more in-depth than it was in the early days.

For example, doctors have come to believe that autism is a spectrum, instead of there being separate diagnoses for asperger’s and autism. They have also come to realize that children with autism can be way more social than previously thought. All of these things play into a diagnosis now, and have given many children the help they need who may have been previously left out.

This has been a constant marker throughout history as observed by Leo Kanner and others who led the way for autism research. In a paper titled Autism: From Research to Practice by Catherine Lord, we learn:

“The constellation of behaviors that we call autism today is the result of astute observations by an eminent clinician, Leo Kanner (1943), of unusual patterns of social, communication, cognitive and motor development co-occurring in a small number of children. At about the same time, but without knowledge of Kanner, Hans Asperger (1944), a German pediatrician, wrote about similar, though not identical, patterns in boys he had seen.

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Through systematic studies, many aspects of these behaviors are now more carefully delineated and better understood. This includes knowing that not all individuals with autism have generally strong intelligence (Fombonne, 2005), that there are genetic components to autism which are sometimes, but not always, familial (Abrahams & Geschwind, 2008), and that autism is not just a disorder of childhood but a truly developmental disorder that affects development and is itself manifested differently across the lifespan (Lord & Spence, 2006).”

The original ADOS was developed by Lord C. and her colleagues The diagnoses of autism was becoming more and more prevalent, and the need for a standardized means of assessment arose.

“As a psychologist trained at UCLA by behaviorists, in North Carolina using the CARS and PEP, and at the Maudsley, Lord, with her colleagues ( Lordet al., 1989) proposed the need for an additional standardized measure, particularly of social communication, which would be based on direct interaction with and observation by a clinician.

The idea was to use the social and communication skills of the clinician to create standardized, but individualized, contexts in which to observe a child’s reciprocal interaction with an unfamiliar but engaging person. The first version of the ADOS was created (Lord, Rutter, DiLavore, & Risi, 2000) to be used with children five years and older in Rutter’s first family genetics study (Bolton et al., 1998) and in a follow-up study of verbal adolescents in North Carolina (Venter et al., 1992).”

Since the first autism diagnostic observation schedule was meant only for children five years and older, over time it became clear that an expansion of the ADOS was needed. Back to the drawing board they went.

Over the years the ADOS has been honed and perfected to include the latest edition the autism diagnostic observation schedule second edition ADOS-2. It can now be administered to children and from 20 months through adults.

What is the difference between ADOS and ADOS-2?

The ADOS was updated with the autism diagnostic observation schedule second edition (ADOS-2).


The ADOS has four modules:

  • Module 1—for children 31 months and older who do not consistently use phrase speech
  • Module 2—for children of any age who use phrase speech, but are not verbally fluent
  • Module 3—for verbally fluent children and young adolescents
  • Module 4—for verbally fluent older adolescents and adults

Gold standard

The ADOS-2 also has updated protocols, revised algorithms, and a new comparison score administration. It is considered the “gold standard” for the observational assessment of autism spectrum disorders.


The autism diagnostic observation schedule second edition has five modules, the same four as above with the addition of a toddler module. The toddler module administration is directed at children between the ages of 20-30 months who do not use phrase speech.

What is phrase speech?

Phrase speech is using sounds in combination of three or more, that can sometimes include verbs, to form phrases with a meaning. For instance, a toddler might imitate the sounds they hear within sentences, insert words or fractions of words they know, and form a request: “Dada take?”

This indicates the toddler understands that sounds make words and words mean certain objects, emotions, or people. They may not be able to form perfect phrases, but they are able to get their point across.

What does verbally fluent mean?

Verbally fluent means someone knows how to form words, phrases, and sentences, and uses them at a developmental level appropriate for their age.

Verbally fluent toddlers would not require the same kind of activities and tasks that younger, or less verbally fluent children would. Thus, the toddler module was born and included in the ADOS-2.

Toddler module

The toddler module of the diagnostic observation schedule second edition is designed to be used for toddlers who, at such a young age, have different needs and abilities than older kids. This addition to the ADOS-2 has allowed for the assessment and diagnosis of children at a younger age than before.

The new toddler module algorithms provide “ranges of concern” instead of cut off scores. These ranges help the administrator with clinical impressions, instead of formal classification. It provides an indicated risk of ASD and guides in further monitoring.

Who can administer an ADOS?

A valid assessment requires training, this means that only people who are qualified can administer the ADOS-2. Training is available through various means. Trainees should have a background that includes experience with autism.

Typically people who go through the training are professionals who will use it in their practices. Sometimes schools will send some of their staff for this additional training as well.

Training options

There are three specific training options for the ADOS-2. Training is available to accommodate almost any schedule. The training options are as follows:

  • Live, in-person training For this training, people will attend the clinical workshop led by an instructor. These training sessions typically last two days. It is designed for those using ADOS-2 in clinical practice or research
  • Online self led study For this, the trainee would complete training sessions online. This again is for people who will be using the ADOS-2 in clinical practice, but excludes those who will be using it for research (those trainees are required to attend in person). It covers all the same material as the in-person sessions, and is about 14 hours in length. This has now replaced the original ADOS dvd training package.
  • Toddler module training This training option is for those who have previous training with the ADOS modules 1-4, have been using it in their practice, and just need to know the updated content, and the training in the toddler module. This includes online training videos (which replaced the toddler training dvd) for module 5 only with training videos guidebook, and training protocol booklets (these materials are now offered in digital form online, instead of training dvds). This training has a run time of 4-5 hours.

What happens after the training is complete?

So, how does someone go from the training, to administering and diagnosing? Can anyone do it? Can parents administer an ADOS-2 with their kids on their own as long as they have done the training?

These questions are pertinent and in the answers we will find what the level of excellence is required for someone to administer the ADOS-2 to our child. When it comes to autism spectrum classifications, we want the utmost care given to us and our children.


To purchase and use the kit you must have a Master’s degree in Psychology or a related field, a Bachelor’s degree in Psychology or a related field, plus additional training. You also want to complete the aforementioned training before administering it.

Purchase the kit

The kit for the diagnostic observation schedule second edition includes all of the materials needed for all five modules. Each module has its own protocol booklet and expanded training guidebook covering how to observe, take notes, code the behaviors, then score each one using the appropriate algorithm.

It is available in English as well as Czech, Danish, Dutch, Finnish, French, German, Italian, Norwegian, and Swedish.

With qualifications, training and kit acquired, it is time for the administration of the ADOS-2.

Test and assess

Next comes the actual administration. As the patient progresses through each activity, all the information is collected and documented. It is then added to the rest of the data gathered and an assessment is made, based on the whole of the collected data. Then the diagnosis can be determined.


In order to diagnose autism spectrum disorders, someone must be qualified to do so. It’s important to note that going through the full training on how to administer an ADOS, does not qualify someone to diagnose. Some professionals that can be qualified to actually diagnose autism spectrum disorders are:

  • child psychologists
  • pediatric neurologists
  • child psychiatrists
  • developmental pediatricians

Each of these professionals have completed the required training and education level, and therefore are qualified to assess and diagnose autism.

Knowing who is qualified to administer the ADOS-2 can ease parent’s minds knowing that their children will be looked after properly. That being said, if you or your child are uncomfortable with a professional, or feel that they are not a good fit for your family, it is ok to switch doctors.

Summing up

The ADOS and the upgraded ADOS-2 have been used as part of a complex system of assessments used to help diagnose autism spectrum disorders, as well as to issue non-autism spectrum diagnosis.

It has developed over many years and has evolved along with the science, research, and clinical practice over time. What is considered the “gold standard” now, may change in the future. For now, we can be assured that our families are receiving the most up-to-date measures based on current data.

Now that we know what an autism diagnostic observation schedule is, we can understand what our child will embark upon when they attend their appointment. These assessments are very involved, very effective, and require training of professionals to administer.

When the need for diagnosing autism spectrum disorders arises, we can have confidence that our child will be in good hands. I hope this overview has brought some encouragement and enlightenment, and wish you and your child all the happiness as you head off in whatever direction an ADOS sends you.


For more information on the ADOS-2 kit, visit https://www.wpspublish.com/


Lord, C., Risi, S., Lambrecht, L., Cook, E. H., Jr, Leventhal, B. L., DiLavore, P. C., Pickles, A., & Rutter, M. (2000). The autism diagnostic observation schedule-generic: a standard measure of social and communication deficits associated with the spectrum of autism. Journal of autism and developmental disorders, 30(3), 205–223.

Lord C. E. (2010). Autism: from research to practice. The American psychologist, 65(8), 815–826. https://doi.org/10.1037/0003-066X.65.8.815

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