title: A comparison of children and adolescent's self-report and parental report of the PedsQL among those with and without autism spectrum disorder.
abstract: Children and adolescents with autism spectrum disorders (ASD) are understood to experience a reduced quality of life compared to typically developing (TD) peers. The evidence to support this has largely been derived from proxy reports, in turn which have been evaluated by Cronbach's alpha and interrater reliability, neither of which demonstrate unidimensionality of scales, or that raters use the instruments consistently. To redress this, we undertook an evaluation of the Pediatric Quality of Life Inventory™ (PedsQL), a widely used measure of children's quality of life. Three questions were explored: (1). do TD children or adolescents and their parents use the PedsQL differently; (2). do children or adolescents with ASD and their parents use the PedsQL differently, and (3). do children or adolescents with ASD and TD children or adolescents use the PedsQL differently? By using the scales differently, we mean whether respondents endorse items differently contingent by group.
  
  
  
  We recruited 229 children and adolescents with ASD who had an IQ greater than 70, and one of their parents, as well as 74 TD children or adolescents and one of their parents. Children and adolescents with ASD (aged 6-20 years) were recruited from special primary and secondary schools in the Amsterdam region. Children and adolescents were included based on an independent clinical diagnosis established prior to recruitment according to DSM-IV-TR criteria by psychiatrists and/or psychologists, qualified to make the diagnosis. Children or adolescents and parents completed their respective version of the PedsQL.
  
  
  
  Data were analysed for unidimensionality and for differential item functioning (DIF) across respondent for TD children and adolescents and their parents, for children and adolescents with ASD and their parents, and then last, children and adolescents with ASD were compared to TD children and adolescents for DIF. Following recoding the data, the unidimensional model was found to fit all groups. We found that parents of and TD children and adolescents do not use the PedsQL differently ([Formula: see text] = 64.86, p = ns), consistent with the literature that children and adolescents with ASD and TD children and adolescents use the PedsQL similarly ([Formula: see text] = 92.22, p = ns), though their score levels may differ. However, children and adolescents with ASD and their parents respond to the PedsQL differently ([Formula: see text] = 190.22, p < 0.001) and contingently upon features of the child or adolescent.
  
  
  
  We suggest this is due to children or adolescents with ASD being less forthcoming with their parents about their lives. This, however, will require additional research to confirm. Consequently, we conclude that parents of high-functioning children with ASD are unable to act as reliable proxies for their children with ASD.
authors.affiliation: School of Psychology, Deakin University, 75 Pigdons Rd, Waurn Ponds, VIC, 3216, Australia. mark.stokes@deakin.edu.au.
authors.forename: M A
authors.initials: MA
authors.lastname: Stokes
authors.affiliation: School of Psychology, Deakin University, 75 Pigdons Rd, Waurn Ponds, VIC, 3216, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Kornienko
authors.affiliation: Section Clinical Developmental Psychology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.|EMGO Institute for Health and Care Research, Amsterdam, The Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: Scheeren
authors.affiliation: Section Clinical Developmental Psychology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.|EMGO Institute for Health and Care Research, Amsterdam, The Netherlands.
authors.forename: H M
authors.initials: HM
authors.lastname: Koot
authors.affiliation: Section Clinical Developmental Psychology, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.|EMGO Institute for Health and Care Research, Amsterdam, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Begeer
mesh_terms: D000293:Adolescent; D000328:Adult; D000067877:Autism Spectrum Disorder / Q000523:psychology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D019727:Proxy; D011594:Psychometrics / Q000379:methods*; D015203:Reproducibility of Results; D057566:Self Report; D018434:Sickness Impact Profile; D055815:Young Adult
keywords: ASD; Autism; Child; Children; Differential item function; Item response analysis; Parent; PedsQL; Proxy reporting