Replication study of ADOS-2 Toddler Module cut-off scores for autism spectrum disorder classification.
The ADOS-the Toddler Module cut-offs of 12 and 10 still work great — trust them, but watch for emotion codes that might shift scores.
01Research in Context
What this study did
The team tested the ADOS-the Toddler Module on the kids months.
They compared the test scores to expert clinical diagnosis to see if the cut-offs still work.
All children were already referred for possible autism, so the sample was high-risk.
What they found
The cut-off of 12 on Algorithm 1 caught autism with a large share accuracy.
The cut-off of 10 on Algorithm 2 also hit a large share accuracy.
These numbers match the original 2013 Toddler Module study almost exactly.
How this fits with other research
de Bildt et al. (2011) found similar strong accuracy in Dutch kids using older modules — this new study shows the toddler version holds up just as well.
Bennett et al. (2008) saw lower accuracy in Hispanic children with mild symptoms. The current study used a more diverse sample and still found high accuracy, suggesting the toddler cut-offs may be more robust than the older module 2/3 ones.
Ten Hoopen et al. (2025) showed that emotion codes like overactivity can nudge scores up or down by a point or two. This matters because a single point could push a toddler across the 10 or 12 cut-off, so watch for those codes during testing.
Why it matters
You can keep using the standard ADOS-the Toddler cut-offs with confidence. If a child scores right at 10 or 12, double-check the emotion codes and consider repeat testing before making big decisions.
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Join Free →When you score a toddler at 10 or 12, pause and review the emotion codes — adjust your clinical judgment if overactivity or anxiety pushed the score.
02At a glance
03Original abstract
The Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) has been regarded as the gold standard assessment of autism spectrum disorder (ASD). While clinical validity of ADOS-2 Modules 1-4 have been extensively studied, there has been very limited research examining the clinical validity of ADOS-2 Toddler Module. The goal of this study was to examine alignment of the ADOS-2 Toddler Module classification with clinicians' determination of ASD, with assessing cut-off scores for diagnosing ASD in toddlers. A total of 412 toddlers ages 12-30 months who received ADOS-2 Toddler Module as well as a best estimate clinical (BEC) diagnosis, were included in this study. ADOS-2 Toddler Module cut-off scores were determined using the appropriate algorithms (Algorithm 1 for toddlers aged 12-20 months and those aged 21-30 months with <5 words, Algorithm 2 for toddlers aged 21-30 months with 5 words or more). Receiver operating characteristic (ROC) curves were used to assess cut-off scores that optimized sensitivity and specificity when compared against BEC diagnosis. The selected cut-off scores were examined using frequency tables to compare ADOS-2 classification against BEC diagnosis. For Algorithm 1, classification statistics were optimized at the cut-off score of 12 with an area under the curve (AUC) of 0.92. For Algorithm 2, classification statistics were optimized at the cut-off score of 10 with an AUC of 0.96. The ADOS-2 Toddler Module classification is strongly aligned with BEC diagnosis. The optimal cut-off scores identified in the current study reflect the same results configured by the prior study. LAY SUMMARY: ADOS-2 Toddler Module has been widely used for the ASD assessment, but there have been limited research on its clinical validity. This study is the first replication of the ADOS-2 Toddler Module with a large independent sample. We examined alignment of the ADOS-2 Toddler Module classification with clinicians' determination of ASD, with assessing cut-off scores, and confirmed the clinical validity of ADOS-2 Toddler Module. Cut-off scores of ADOS-2 Toddler Module cited in the manual yielded best clinical utility for diagnosing ASD in toddlers.
Autism research : official journal of the International Society for Autism Research, 2021 · doi:10.1002/aur.2496