Originally published on 8/2/22 and Updated on 10/30/25

How Do I Choose the Most Accurate Autism Test For My Client? 

Identifying autism shouldn’t depend on a single measure or assumption. When a person is seeking a diagnosis for autism, they undergo autism assessment, not autism testing. A person cannot “pass” or “fail” an autism test; however, an autism assessment is a tool that helps a clinician to use their years of training and experience to make a diagnosis. A clear diagnosis—one your client can trust, and you can feel confident delivering—is the result of a comprehensive evaluation, generally involving a team of health and education professionals. The Centers for Disease Control and Prevention (CDC) recommends that clinicians gather information from several sources, including the parents’ account of their child’s development, diagnostic assessments, and professional observations (CDC, 2022).   

The diagnostic tools you select are a critical part of a comprehensive evaluation. Here’s a quick primer on the types of assessments many clinicians use in an autism evaluation.   

Developmental Monitoring and Early Screening Tools 

Developmental monitoring takes place as caregivers and pediatric health professionals track developmental milestones at home or in a clinical setting. Parents and health care providers use these quick questionnaires and checklists to identify children whose development may be atypical and who may have a higher likelihood of autism.  Tools such as the Modified Checklist for Autism in Toddlers, Revised (M-CHAT-R) are effective for this kind of early screening.

Rating Scales 

Rating scales are typically used to determine how severe the symptoms or characteristics of a condition are. They often ask parents, the client, or observers to rate different behaviors or characteristics on a scale of progressive intensity. Examples of autism rating scales include:  

• Autism Spectrum Rating Scales™ (ASRS®) 
• Childhood Autism Rating Scale, Second Edition (CARS®2)
• Social Responsiveness Scale, Second Edition (SRS™-2) 

Interviews 

Diagnostic interviews can be either structured, where the interviewer asks standardized questions in a pre-determined sequence, or semi-structured, where the interviewer has some flexibility to individualize follow-up questions. Interview formats can be particularly valuable tools for identifying strengths and collaborating with parents, teachers, and caregivers. The Autism Diagnostic Interview–Revised (ADI®-R) and  Monteiro Interview Guidelines for Diagnosing the Autism Spectrum, Second Edition (MIGDAS™-2) are both interview-based assessments.

Observations  

Observations typically involve structured interactions between an evaluator and the person being evaluated. Interactions may involve objects, movements, or tasks—and the goal of each activity is to provide the child with opportunities to communicate with the observer.  The Autism Diagnostic Observation Schedule, Second Edition (ADOS®-2) uses observation in a play-based interaction to measure autism traits. 

Most of the time, an autism evaluation includes more than one type of assessment so clinicians can create a complete picture of a child’s development. Given the range of available tools, how do you go about choosing which ones to use? Here are a few questions to consider as you weigh your options. 

Does the Assessment Identify Autism Accurately?  

You’ll need a diagnostic tool that is sensitive, which means it correctly identifies the diagnostic criteria for autism specified by the Diagnostic and Statistical Manual for Mental Health Disorders, Fifth Edition, Text Revision (DSM-5-TR). The assessment should be specific, which means it identifies typical behaviors. An autism assessment should also be reliable, which means that when people administer it over and over, the results are the same. In other words, you need a measure that researchers and health professionals trust because it correctly identifies the characteristics of autism.   

Learn how to combine trusted autism assessments to save time and generate more accurate results. 

Does the Assessment Fit the Characteristics and Life Experience of Your Client?

The “Guidelines for Assessments and Evaluations” of the American Psychological Association (APA) suggest that an evaluator consider the age, sex, ethnicity, and primary language of the client when deciding which assessment to use. The guidelines also recommend that evaluators know the demographics of the people included in the normative sample for the assessment.   

The data you gather from an assessment may not be accurate if your client’s characteristics aren’t represented among the norm group, the APA says (2020). If an assessment relies on tasks that have no cultural familiarity to your client, the results could be similarly skewed. When a mismatched assessment provides misleading results, clients may not get the services they need—and unfair health disparities can result (Thunt, 2021).  

It's also important to factor in the possible effects of sex and gender norms as you select assessments. Research indicates that assessments differ in their ability to capture autism traits accurately in girls and women (Cook et al., 2024). Interviews can be particularly effective for providing a deeper understanding of how gender expectations may be affecting the presentation of autistic traits in your client. They may also give you greater insight into the ways autism is affecting someone’s daily functioning, mental health, and relationships. 

Learn more: Autism is Cross-Cultural. Shouldn’t Your Assessments Be, Too? 

Is the Assessment Available in the Language You Need?     

When people take assessments in languages they are still learning, the results may be affected by the linguistic demands of the test, rather than by autism. Autism may be under-identified among students who are English-language learners, possibly because autism and English-language learners sometimes have delays, challenges, or differences in  

• social communication,  
• pragmatic speech,  
• language acquisition,  
• nonverbal communication, and/or  
• social behaviors.  

If an autism assessment tool isn’t available in the language you need, experts recommend using assessment tools that aren’t dependent on language. It’s also a good idea to interview multiple informants and to provide flexible time requirements during testing.  

Learn more: Understanding Language in Autism—Alexithymia, Echolalia, and Beyond.  

What Other Assessments Will You Need to Complete the Evaluation?  

One of the goals of an evaluation is determining whether symptoms could be better explained by another health condition. For that reason, your diagnostic team will likely need to determine whether any other conditions are causing symptoms that look like autism characteristics. Health conditions such as these can complicate an autism evaluation:  

• attention-deficit/hyperactivity disorder (ADHD) 
• specific learning disabilities (SLDs) 
• anxiety  
• depression  
• bipolar disorder  
• intellectual development disorder (IDD) 
• social communication disorder (SCD) 
• obsessive compulsive disorder (OCD) 
• Tourette’s syndrome  

In addition to looking for comorbidities and overlapping symptoms, many clinicians also assess adaptive behavior skills. Adaptive behavior assessments show which areas of a student’s life may be impacted by the core characteristics of autism or another condition. Studies show that parents aren’t just concerned about a formal diagnosis, but about the child’s daily functional needs—whatever the diagnosis turns out to be.  

Learn more: Adaptive Behavior Assessment 

Where Will the Assessment Be Administered?     

It’s important to consider where and how you’ll administer an assessment. The amount of time you’ll need to complete the evaluation and the cost of an assessment are two other practical aspects to consider.   

In some instances, such as rural locations where health care and psychological services may be limited, telehealth services can improve access to care (Zwaigenbaum et al., 2021). Even so, not every assessment has been validated for use online (Spain et al., 2022). The ADOS-2 is validated for in-person use, but other auxiliary diagnostic tools are available for use as telehealth assessments.  

Explore the WPS Autism Assessment Tool Kit for more information on assessment features. 

What Training Will You Need to Feel Confident Administering, Scoring, and Interpreting the Test?      

Becoming skilled at giving and interpreting assessments doesn’t happen overnight. It takes experience and ongoing training, especially as assessments are revised and updated in response to new research. As you make decisions about which tests to select, consider the resources available to help train you in the use of each tool.  

Can you participate in webinars, workshops, or continuing education to better understand test items and how to interpret responses? Do you have access to seasoned assessment professionals to guide you, not only in choosing the best test for the situation but in using the tool to identify autism? Are there mentors at your clinic or in your school who can walk you through the process?  

It’s important to say that trained, experienced professionals may be able to identify autism traits without using a formal assessment—but in many settings, unlocking services and supports requires the use of a validated diagnostic tool. The better you understand your client’s characteristics and needs, the better you’ll be at choosing the best  diagnostic tool for each person in your care. 

We invite you to build your professional knowledge in autism assessment through WPS ProLearn®.  

Training

ADOS-2 Clinical Workshop

WPS offers 2-day workshops that teach, through instruction and demonstration, how to use the ADOS-2 to assess and diagnose autism.

View Schedule >

ProLearn® On-Demand Webinar

Autism Today: Applying Diagnostic Criteria to Diverse Populations

This webinar reviews current autism diagnostic criteria, contrasts medical and social models, and explores research on diverse presentations across populations.

Learn More >