Psychometric evaluation of the Autism Symptom Dimensions Questionnaire

Area of Science:

• Psychometrics
• Clinical Psychology
• Neurodevelopmental Disorders

Background:

• The Autism Symptom Dimensions Questionnaire (ASDQ) is an informant-reported measure used to assess autism spectrum disorder (ASD).
• Previous psychometric findings for the ASDQ require replication and extension in diverse samples.
• Valid and reliable measures are crucial for accurate ASD diagnosis and effective intervention.

Purpose of the Study:

• To replicate and extend previous psychometric findings for the Autism Symptom Dimensions Questionnaire (ASDQ).
• To evaluate the factor structure, measurement invariance, reliability, construct validity, screening and diagnostic efficiency, and detection of reliable change for the ASDQ.

Main Methods:

• A cross-sectional design was employed with two independent samples.
• The study included 3366 children and adolescents (aged 2-17 years), with 1399 diagnosed with ASD.
• A small case series was also included to examine specific psychometric properties of the ASDQ.

Main Results:

• The ASDQ exhibited strong psychometric properties, including a replicable factor structure and strong measurement invariance.
• Adequate-to-excellent scale and conditional reliability, strong convergent and discriminant validity, and good screening efficiency were observed.
• The ASDQ demonstrated good test-retest stability and the potential to detect reliable change, though diagnostic efficiency was weak.

Conclusions:

• The ASDQ possesses favorable and well-replicated psychometric properties across two samples.
• Its strengths lie in screening and detailed clinical characterization of the autism behavioral phenotype, aligning with DSM-5 criteria.
• The ASDQ's reliability and ability to detect change suggest its utility in monitoring intervention response.