Autism spectrum disorder (ASD), commonly referred to as autism, is a neurodevelopmental condition that 1 in 36 children is diagnosed with (Centers for Disease Control and Prevention, 2023). Children with autism experience the world differently compared to their neurotypical peers. They may exhibit repetitive behaviors, restricted interests, and delays in their social communication skills.  


Research shows that early interventions when a child’s brain is most rapidly developing are key to achieving the best possible outcomes (NICHD, 2021). As such, an early autism diagnosis can help families find the resources needed to support their child’s unique needs. Navigating the somewhat complex diagnostic process can feel daunting for parents and caregivers. In this article, we offer clarification on the autism diagnostic process from screening to testing and explain how professionals use various assessment tools. 

Autism Screenings 

The first step in the process involves developmental screening. Screenings are a common component of baby and young children’s pediatric well visits. The Ages and Stages Questionnaire (ASQ) is one screening tool that many medical professionals and educators use to identify those at risk for developmental delays. 


Professionals use screening tools such as the ASQ to assess a child’s developmental strengths and any areas of delay. They evaluate various areas of a child’s functioning, including motor skills, communication, social-emotional functioning, and problem-solving. The results of a developmental screening cannot offer a diagnosis of autism or any other disorder. However, they provide valuable information regarding the next steps. If a child’s screening results show an increased risk for autism or another developmental delay, your child’s pediatrician would recommend diagnostic testing or further monitoring.  

Importance of Autism Screenings  

Despite screenings not resulting in a diagnosis, they play a vital role in the diagnostic process. Autism is a spectrum disorder. Therefore, the presentation of symptoms can vary significantly from one child to another. Some children with autism are overlooked due to their delays being more subtle. This results in many children not receiving a diagnosis until they are of school age. Developmental screenings help identify delays as early as possible, leading to further testing. If a diagnosis is made through additional testing, the child may have access to therapy and other resources sooner than they would have otherwise.  

autism screening

Autism Diagnostic Testing 

If an autism screening tool identifies a child as “at risk” for autism, the next step is typically a referral for a diagnostic evaluation. Through diagnostic testing, a qualified diagnostician identifies whether an individual meets the criteria for an autism diagnosis based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).  


To identify if a child meets the criteria for an autism diagnosis, the diagnostician completes a comprehensive evaluation. These evaluations include caregiver interviews, direct observations, and formal diagnostic tests such as the Autism Diagnostic Observation Schedule (ADOS) and the Gilliam Autism Rating Scale (GARS). Evaluations typically last from 1.5-4 hours in duration.


Who can make an autism diagnosis? 

Diagnostic testing for autism can only be conducted by a qualified professional with the credentials and training required to administer testing and confirm a diagnosis. Qualified diagnosticians include developmental pediatricians, pediatric neuropsychologists, child psychiatrists, and psychologists.  

What tools are used in autism testing? 

Each diagnostician may administer a different combination of assessments to identify whether your child meets the criteria for an autism diagnosis. Some of the diagnostic tools used include: 


Autism Diagnostic Observation Schedule-Second Edition (ADOS-2). This standardized assessment tool is used to evaluate communication skills, social interactions, play, and restricted and repetitive behaviors to assess and diagnose autism spectrum disorders. This assessment can be used with children from 12 months old into adulthood. 

Autism Diagnosis Interview-Revised (ADI-R). The ADI-R is a semistructured interview tool completed with caregivers. The ADI-R assesses reciprocal social interaction, communication and language, and restricted and repetitive behaviors. It is intended for use with children and adults 18 months and above. [Text Wrapping Break] 

Childhood Autism Rating Scale-Second Edition (CARS-2). The CARS-2 is a clinician rating scale that a diagnostician completes after direct observation of the child. CARS-2 can be conducted with children of any age.  

Gilliam Autism Rating Scale-Third Edition (GARS-3). The GARS-3 is used to both identify autism and estimate a child’s level of severity within each domain. It assesses six key areas–restrictive and repetitive behaviors, social interactions, social communication, emotional responses, cognitive style, and maladaptive speech.


Skill-Based Autism Assessments 

Diagnostic evaluation assessments provide vital information that can lead to an autism diagnosis. This diagnosis allows children to access the therapies and other supports necessary to reach their full potential. However, diagnostic assessments don’t necessarily pinpoint exactly where a child is struggling and could use extra support. As such, professionals conduct skill-based assessments following a confirmed diagnosis when creating an individualized treatment plan for a child.  


In ABA, behavior analysts conduct skill assessments to identify areas of particular strength and areas of need. Skill assessments are essential to ensure providers tailor goals to a child’s unique needs rather than a one-size-fits-all approach. These assessments provide ABA clinicians with a starting point for goal planning and offer a baseline for ongoing progress monitoring. 


How are skill assessments different than diagnostic assessments? 

Skill assessments look at whether or not a child has specific skills. Skill assessments commonly used within ABA can be used with anyone, as they are associated with skills, not diagnoses. The results of skill-based assessments cannot provide a diagnosis of autism or any other disorder. Instead, they are used to identify lagging skills in various domains of life to guide clinicians in developing treatment goals.

What skill-based assessments do ABA clinicians use? 

The assessments ABA clinicians use for each child vary based on the child’s age and unique needs. Skill-based assessments commonly used in ABA therapy include: 


Assessment of Basic Language and Learning Skills-Revised (ABLLS-R). The ABLLS-R is a criterion-referenced assessment and curriculum focused on basic language and functional skills. It assesses 544 skills across 25 domains in the areas of language, social interactions, self-help, motor skills, and academics. Clinicians use ABLLS-R with children up to age 12. [Text Wrapping Break] 

Assessment of Functional Living Skills (AFLS). AFLS are another criterion-referenced skill assessment and tracking system. There are 6 AFLS protocols to assess 1,900 skills across many domains, making the AFLS beneficial for assessing children and adults of all ages. The six protocols include basic living skills, home skills, community participation skills, social skills, vocational skills, and independent living skills.  

Verbal Behavior-Milestones Assessment and Placement Program (VB-MAPP). The VB-MAPP focuses primarily on language, social, and pre-academic skills. It is made up of 170 milestones of verbal behavior that a typically developing child would generally achieve by age 48 months.  

Essential For Living (EFL). EFL is an assessment and curriculum tool for children and adults. EFL assesses various skills within behavior, communication, and functional skills domains.


How often are skill assessments conducted? 

Behavior analysts and other ABA professionals conduct skill assessments at least once every six months. The exact timeline for assessment updates may vary based on payor requirements and a child’s individual rate of progress. Often, they are updated more frequently to assess ongoing progress, especially when a child makes more rapid progress through their current goals.  

CentralReach Streamlines the Assessment Process for the Best Possible Outcomes

ABA therapy providers who use CentralReach are able to simplify and expedite their assessment workflows, empowering clinicians to enhance learner outcomes. CentralReach transforms the way behavior analysts conduct assessments, ensuring efficiency with digital solutions tailored to each learner’s unique needs. Upon completion of skills assessments, clinicians use customizable reports to make informed decisions about the development of treatment goals and individualized accommodations. Streamlined assessments result in more time spent doing what matters most–providing high-quality care for the best possible outcomes


Ages and Stages. (2021, April 5). Why screening matters. Ages and Stages. 


Centers for Disease Control and Prevention. (2023, April 4). Data & statistics on autism

spectrum disorder. Centers for Disease Control and Prevention.   


Centers for Disease Control and Prevention. (2022, December 6). Screening and diagnosis of

autism spectrum disorder for healthcare providers. Centers for Disease Control and


CHOP Research Institute. (2020). Childhood Autism Rating Scale, 2nd Edition (CARS2). 


NICHD. (2021, April 19). Early Intervention for Autism. 


Esler, A., Bal, V. H., Guthrie, W., Wetherby, A. M., Weismer, S. E., & Lord, C. (2015). The Autism Diagnostic Observation Schedule, Toddler Module: Standardized Severity Scores. Journal of Autism and Developmental Disorders, 45(9), 2704–2720. 


Functional Living Skills - A Pathway To Independence For People With Developmental Disabilities. (2022, April 28). Functional Living Skills. 


Partington, J. W. (2006). The Assessment of Basic Language and Learning Skills – Revised (ABLLS-R). Walnut Hill, CA: Behavior Analysts, Inc. 


WPS. (n.d.-a). (ADOS®-2) autism diagnostic observation schedule, Second edition.

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