title: Structural hierarchy of autism spectrum disorder symptoms: an integrative framework.
abstract: BACKGROUND
  In an attempt to resolve questions regarding the symptom classification of autism spectrum disorder (ASD), previous research generally aimed to demonstrate superiority of one model over another. Rather than adjudicating which model may be optimal, we propose an alternative approach that integrates competing models using Goldberg's bass-ackwards method, providing a comprehensive understanding of the underlying symptom structure of ASD.
  
  
  METHODS
  The study sample comprised 3,825 individuals, consecutive referrals to a university hospital developmental disabilities specialty clinic or a child psychiatry outpatient clinic. This study analyzed DSM-IV-referenced ASD symptom statements from parent and teacher versions of the Child and Adolescent Symptom Inventory-4R. A series of exploratory structural equation models was conducted in order to produce interpretable latent factors that account for multivariate covariance.
  
  
  RESULTS
  Results indicated that ASD symptoms were structured into an interpretable hierarchy across multiple informants. This hierarchy includes five levels; key features of ASD bifurcate into different constructs with increasing specificity.
  
  
  CONCLUSIONS
  This is the first study to examine an underlying structural hierarchy of ASD symptomatology using the bass-ackwards method. This hierarchy demonstrates how core features of ASD relate at differing levels of resolution, providing a model for conceptualizing ASD heterogeneity and a structure for integrating divergent theories of cognitive processes and behavioral features that define the disorder. These findings suggest that a more coherent and complete understanding of the structure of ASD symptoms may be reflected in a metastructure rather than at one level of resolution.
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Hyunsik
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Cara M
authors.initials: CM
authors.lastname: Keifer
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Rodriguez-Seijas
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Eaton
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Matthew D
authors.identifier: http://orcid.org/0000-0002-7373-6663
authors.initials: MD
authors.lastname: Lerner
authors.affiliation: Department of Psychiatry, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Gadow
mesh_terms: D000293:Adolescent; D000328:Adult; D000067877:Autism Spectrum Disorder / Q000175:diagnosis* / Q000523:psychology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008960:Models, Psychological; D012720:Severity of Illness Index; D055815:Young Adult
keywords: Autism spectrum disorder; Child and Adolescent Symptom Inventory; bass-ackwards; classification; structural hierarchy