title: Psychometric properties of two ADHD questionnaires: comparing the Conners' scale and the FBB-HKS in the general population of German children and adolescents--results of the BELLA study.
abstract: OBJECTIVE
  To examine and compare the psychometric properties of two short screening instruments for children and adolescents suffering from attention deficit-/ hyperactivity disorder (ADHD). The Conners' Hyperactivity Index consists of ten items that assess symptoms of hyperactivity through self-report and parents' proxy. The German ADHD Rating scale (FBB-HKS/ADHS) consists of 20 items that assess the severity and perceived burden of inattention, hyperactivity, and impulsiveness as defined by the ICD-10 and DSM-IV.
  
  
  METHODS
  Within the BELLA module of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS), the parents of 2,863 children and adolescents rated the Conners' Hyperactivity Index and the FBB-HKS.
  
  
  RESULTS
  The internal consistency of item responses was assessed via Cronbach's alpha and showed that both instrument scores were able to obtain a reliable measurement. The factorial validity of the FBB-HKS measurement model as well as the unidimensionality of the Conners' scale was tested by means of exploratory and confirmatory factor analysis (EFA and CFA), indicating satisfactory goodness of fit for the FBB-HKS (RMSEA=0.06) and some deviation from the unidimensionality assumption of the Conners' scale. Stability of results across age could be confirmed with few exceptions. Mean scores differences were found between both sexes, age groups, and different socioeconomic status groups (Winkler-Index) with males, younger respondents, and children with low socioeconomic status displaying more ADHD-related behaviour. Correlation coefficients between the two instruments' scores and other scales assessing emotional and behavioural problems hinted at convergent validity.
  
  
  CONCLUSIONS
  Both instruments' scores showed reliability as well as factorial and convergent/discriminant validity. The pros and cons of the two instruments as well as for which purpose and under which circumstances one of the measures can be favoured must be considered prior to applying such a measure.
authors.affiliation: Department of Psychosomatics in Children and Adolescents, Centre for Obstetrics and Paediatrics, University Clinic Hamburg-Eppendorf, Martinistrasse 52, W29, 20246, Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Erhart
authors.forename: Manfred
authors.initials: M
authors.lastname: Döpfner
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ravens-Sieberer
mesh_terms: D000293:Adolescent; D000296:Adolescent Psychiatry / Q000706:statistics & numerical data; D017677:Age Distribution; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology* / Q000523:psychology; D002648:Child; D002665:Child Psychiatry / Q000706:statistics & numerical data; D005163:Factor Analysis, Statistical; D005260:Female; D005858:Germany / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D008297:Male; D010290:Parents / Q000523:psychology; D011287:Prejudice; D011569:Psychiatric Status Rating Scales / Q000592:standards* / Q000706:statistics & numerical data; D011594:Psychometrics; D015203:Reproducibility of Results; D012650:Self Disclosure; D012720:Severity of Illness Index; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards*