Validity of the Aberrant Behavior Checklist

Background: Autism spectrum disorder (ASD) is considered a life-long disorder with incredibly heterogeneous symptom presentation. The prevalence of ASD is estimated at 1 in 68 in the United States as identified in 2010, and the World Health Organization has listed ASD as one of three top priorities. Further, the socioeconomic burden of this developmental disorder to the U.S. economy is estimated at $126 billion. Given the individual and societal impact of this disorder, an increased effort has been placed on developing interventions to lessen the severity of the core symptoms of ASD. To date, there is no agreed upon outcome measure for measuring change in core autism symptoms in response to clinical trials.

Objectives: One measure that has been proposed as an outcome measure is the Aberrant Behavior Checklist (ABC; Aman et al., 1985a), specifically the Social Withdrawal scale to measure core symptoms of ASD. However, it is unclear if and how well this subscale truly measures core symptoms of autism. Thus, the purpose of this project is to expand upon existing psychometric work on the ABC and examine the validity of the ABC subscales in relation to other measures designed to assess core symptoms of autism.

Methods: Participants were drawn from a sample of children with an ASD diagnosis who participated in the Simons Simplex Collection. The primary measure of interest for this project is the Aberrant Behavior Checklist (ABC; Aman et al., 1985a) which contains 58 items that comprise five subscales: Irritability, Social Withdrawal, Stereotypic Behavior, Hyperactivity/Noncompliance, and Inappropriate Speech. A total of 2709 participants have a completed ABC and were included in this project. Preliminary analyses included correlations between the subscales of the ABC and other measures of core symptoms of autism including the Autism Diagnostic Observation Schedule, Repetitive Behavior Scale Revised, and the Social Communication Questionnaire.

Results: Small to medium significant correlations were observed between the five subscales of the ABC and all measures of core autism symptoms listed above. To examine the validity of the ABC using multiple methods of assessment and multiple constructs, additional analyses will be conducted using confirmatory factor analysis and exploratory structural equation modeling. Further, measures expected to diverge, or measure constructs other than core autism symptoms will be included in the final analyses.

Conclusions: Several studies have examined the factor structure of the ABC; however, the methodology and statistics used have been limited. The current project extends upon previous work by examining the construct, convergent, and divergent validity of the ABC in a large sample of individuals with ASD using more sophisticated statistical techniques. This approach allows for examination of possible relationships between scores on the ABC and measures expected to converge and diverge with the ABC whereas traditional correlational methods cannot examine underlying constructs which assessment tools are designed to measure. Better understanding what constructs the subscales of the ABC measures, with an emphasis on the Social Withdrawal scale, is imperative as it is being used as an outcome measure in treatment trials.