Concordance of the Adaptive Behavior Assessment System, second and third editions

Area of Science:

• Psychology
• Developmental Psychology
• Clinical Psychology

Background:

• Adaptive functioning assessments are vital for diagnosis, educational planning, and legal evaluations.
• Ensuring the relevance of adaptive functioning measures requires periodic updates and understanding version equivalence.
• Equivalence data is essential for tracking changes in adaptive skills over time.

Purpose of the Study:

• To examine the equivalence between the second (ABAS-2) and third (ABAS-3) editions of the Adaptive Behavior Assessment System.
• To compare scores from ABAS-2 and ABAS-3 in mixed clinical samples using between-group and within-group designs.

Main Methods:

• Two studies were conducted comparing ABAS-2 and ABAS-3 scores in clinically referred children.
• Study 1 used between-group comparisons of large samples assessed on either ABAS-2 or ABAS-3.
• Study 2 used within-group comparisons of children assessed on both ABAS-2 and ABAS-3.

Main Results:

• No significant differences in IQ scores were found between ABAS-2 and ABAS-3 groups.
• ABAS-2 scores were consistently lower than ABAS-3 scores across Conceptual, Practical, and General Adaptive Composite scales in both studies.
• The Practical composite showed the largest score difference and lowest concordance between ABAS versions.

Conclusions:

• ABAS-3 scores tend to be higher than ABAS-2 scores in clinical populations.
• Awareness of score discrepancies between ABAS versions is critical for accurate interpretation in clinical, educational, and forensic contexts.
• These findings highlight the need for careful consideration when interpreting changes in adaptive functioning scores across different ABAS editions.