What Are Common ASD Assessment Tools?

What are you even evaluating for??

The most common autism spectrum disorder assessment measures include, the autism diagnostic observation schedule, second edition (ADOS-2), the autism diagnostic interview, revised (ADI-R), social communication questionnaire (SCQ), Gilliam autism rating scale, third edition (GARS-3), childhood autism rating scales, second edition (CARS-2), autism spectrum rating scales (ASRS), and social responsiveness scale, second edition (SRS-2). There are some others of course; however, these are the instruments that are generally used by psychologists most often and have the most solid psychometric evidence in the research. There are other self-report measures available on the internet, but those are typically less valid and for informational or screening purposes only, so you should be careful to self-diagnose or rely on an evaluation using only self-report measures. Additionally, though not autism measures specifically, there are other commonly administered measures that are required for an autism-based assessment, especially if the assessment will be used to justify autism or developmentally delayed-based services. Typically, some form of adaptive functioning (practical, independent skills) are assessed jointly with parents and/or teachers. These would include the adaptive behavior assessment system (ABAS-3) and the Vineland adaptive behavior scales, third edition (Vineland-3). Most often, a measure of intellectual functioning is required as well, especially if determining level of support required. For those with limited language especially, there are certain intellectual assessments that are more likely to be used, including the comprehensive test of nonverbal intelligence, second edition (CTONI-2), the test of nonverbal intelligence, fourth edition (TONI-4), and the special nonverbal composite (SNC) of the differential abilities scales, second edition (DAS-2). Finally, depending on the nature of the assessment, common language assessments that evaluate pragmatic language skills specifically include, the receptive, expressive, and social communication assessment (RESCA), the test of pragmatic language, second edition (TOPL-2), social language development test (SLDT), and the clinical evaluation of language fundamentals, fifth edition- metalinguistics test (CELF-5-META).

Now, to qualify all this, and this may be surprising to some, but, the idea of the Autism Diagnostic Observation Schedule, Second Edition, or ADOS-2, being the “gold standard” of testing for autism, is actually not supported or endorsed by most clinical psychologists, including the developers of the assessment. While the ADOS-2 and ADI-R (the ADOS-2’s caregiver interview component) can help with diagnostic accuracy in certain cases in which the assessments are appropriate, the overall accuracy for these measure, tends to be unimpressive, along with reduced inter-rater reliability (two people giving the same score for a particular item). This is especially true for those who are on the “outer ends” of the spectrum, meaning very low or very high support needs, or those with co-occurring motor, sensory, or intellectual disabilities, as confirmed by the research.

In fact, recent studies have brought light to the lacking reliability, sensitivity, and specificity (ability to reduce false positive and false negative errors) of many common autism assessment measures including the ADOS-2 and ADI-R, as well as the ASRS, CARS-2, and Gilliam-3, three other commonly used autism assessment measures, further highlighting the need and importance of clinical judgment, and potential over-reliance of behavioral patterns incongruent with societal norms. Additionally, accuracy and reliability of diagnoses from assessment tools have been shown to be considerably higher in research as opposed to clinical settings. Of note, self-report and parent report questionnaires, tend to result in a significantly high number of false positives, that is, diagnosing someone with autism who does not truly have autism, which ironically is actually counterintuitive to what most insurance companies desire in terms of the services and care someone with autism is eligible for. Interestingly, the research has shown that for teenagers and young adults, sometimes there is an increased diagnostic challenge, secondary to the high rates of anxiety and mood disorders, which can also mimic restricted interests or behavior, within these populations, both in the neurodivergent and neurotypical populations.

The moral of the story is this: over-reliance on testing and any particular diagnostic tools should be cautioned against and should never substitute for clinical training and professional judgment. It should be noted that there are NO diagnostic tools or assessments that are required to be administered in order for a clinician to diagnose autism. The degree and training of the clinical is most important. This has become more complex largely because of insurance companies, who will sometimes request a particular assessment (often ADOS of ADI) or authorize more units (and thus pay more money) if particular assessments are used. For autism specifically, it is more important, especially from a neuropsychological point of view, to identify a patterns of score, strengths and weaknesses, than to analyze the results of any one domain or assessment tool, especially for females and high maskers. Though an autism diagnosis, when accurate, can serve as a pathway to much-needed services and supports, ultimately, because of the heterogeneity within autism spectrum disorder, it is more critical to describe the unique strengths and barriers for the individual in order to provide appropriate and individualized recommendations for intervention.