title: Bifactor Models Show a Superior Model Fit: Examination of the Factorial Validity of Parent-Reported and Self-Reported Symptoms of Attention-Deficit/Hyperactivity Disorders in Children and Adolescents.
abstract: BACKGROUND
  Various studies have demonstrated that bifactor models yield better solutions than models with correlated factors. However, the kind of bifactor model that is most appropriate is yet to be examined. The current study is the first to test bifactor models across the full age range (11-18 years) of adolescents using self-reports, and the first to test bifactor models with German subjects and German questionnaires.
  
  
  METHODS
  The study sample included children and adolescents aged between 6 and 18 years recruited from a German clinical sample (n = 1,081) and a German community sample (n = 642). To examine the factorial validity, we compared unidimensional, correlated factors and higher-order and bifactor models and further tested a modified incomplete bifactor model for measurement invariance.
  
  
  RESULTS
  Bifactor models displayed superior model fit statistics compared to correlated factor models or second-order models. However, a more parsimonious incomplete bifactor model with only 2 specific factors (inattention and impulsivity) showed a good model fit and a better factor structure than the other bifactor models. Scalar measurement invariance was given in most group comparisons.
  
  
  CONCLUSIONS
  An incomplete bifactor model would suggest that the specific inattention and impulsivity factors represent entities separable from the general attention-deficit/hyperactivity disorder construct and might, therefore, give way to a new approach to subtyping of children beyond and above attention-deficit/hyperactivity disorder.
authors.affiliation: Department of Psychiatry, Psychosomatics and Psychotherapy in Childhood and Adolescence, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Klaas
authors.initials: K
authors.lastname: Rodenacker
authors.forename: Christopher
authors.initials: C
authors.lastname: Hautmann
authors.forename: Anja
authors.initials: A
authors.lastname: Görtz-Dorten
authors.forename: Manfred
authors.initials: M
authors.lastname: Döpfner
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D001288:Attention; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000523:psychology*; D002648:Child; D002652:Child Behavior / Q000523:psychology*; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008960:Models, Psychological; D010287:Parent-Child Relations; D010290:Parents / Q000523:psychology*; D057566:Self Report; D011795:Surveys and Questionnaires