Harmonizing two measures of adaptive functioning using computational approaches: prediction of vineland adaptive behavior scales II (VABS-II) from the adaptive behavior assessment system II (ABAS-II) scores.
Corinna Smith, Alexandra Lautarescu, Tony Charman and 12 others
PMID 39627866WHAT IT FOUND
ABAS scores can predict VABS scores with an error of about 5 points, but this exceeds the 2–3.75 point clinical significance threshold.
The conversion is most accurate when using age, diagnosis, and ABAS raw scores alongside the composite.
Key findings
01The median absolute prediction error for VABS scores from ABAS data was 4.96 points for the full sample and 4.80 points for the autism-only group.
02This prediction error is larger than the minimum clinically significant difference for the VABS, which is 2 to 3.75 points.
03Adding age, sex, diagnosis, and ABAS raw scores to the model reduced error compared to using the ABAS composite score alone, but the improvement was smaller than the clinically significant difference.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The prediction error, while statistically small, exceeds the clinically significant difference threshold for the VABS, limiting its utility for individual patient care. The study focused on composite scores and did not examine the conversion of specific domain scores (e.g., communication, daily living skills). The sample was drawn from a specific research network (OBI-POND) in Ontario, Canada, which may limit generalizability to other populations or settings.
Declared interests
The study was funded by the Natural Sciences and Engineering Research Council of Canada and the New Frontiers in Research Fund. No commercial conflicts of interest were reported.
The easy way to misread this
Do not assume that ABAS and VABS scores are interchangeable in clinical practice. Although the statistical correlation is high, the prediction error of ~5 points is larger than the 2–3.75 point difference considered clinically significant on the VABS, so a converted score cannot reliably replace an actual VABS assessment.