title: The context dependency of the self-report version of the Strength and Difficulties Questionnaire (SDQ): a cross-sectional study between two administration settings.
abstract: BACKGROUND
  The Strength and Difficulties Questionnaire (SDQ) is a screening instrument for psychosocial problems in children and adolescents, which is applied in "individual" and "collective" settings. Assessment in the individual setting is confidential for clinical applications, such as preventive child healthcare, while assessment in the collective setting is anonymous and applied in (epidemiological) research. Due to administration differences between the settings it remains unclear whether results and conclusions actually can be used interchangeably. This study therefore aims to investigate whether the SDQ is invariant across settings.
  
  
  METHODS
  Two independent samples were retrieved (mean age = 14.07 years), one from an individual setting (N = 6,594) and one from a collective setting (N = 4,613). The SDQ was administered in the second year of secondary school in both settings. Samples come from the same socio-geographic population in the Netherlands.
  
  
  RESULTS
  Confirmatory factor analysis showed that the SDQ was measurement invariant/equivalent across settings and gender. On average, children in the individual setting scored lower on total difficulties (mean difference = 2.05) and the psychosocial problems subscales compared to those in the collective setting. This was also reflected in the cut-off points for caseness, defined by the 90th percentiles, which were lower in the individual setting. Using cut-off points from the collective in the individual setting therefore resulted in a small number of cases, 2 to 3%, while ∼10% is expected.
  
  
  CONCLUSIONS
  The SDQ has the same connotation across the individual and collective setting. The observed structural differences regarding the mean scores, however, undermine the validity of the cross-use of absolute SDQ-scores between these settings. Applying cut-off scores from the collective setting in the individual setting could, therefore, result in invalid conclusions and potential misuse of the instrument. To correctly apply cut-off scores these should be retrieved from the applied setting.
authors.affiliation: Department of Epidemiology, CAPHRI School for Public Health and Primary Care, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands; Academic Collaborative Centre for Public Health Limburg, Public Health Service Southern Limburg, Geleen, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Hoofs
authors.affiliation: Department of Epidemiology, CAPHRI School for Public Health and Primary Care, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
authors.forename: N W H
authors.initials: NW
authors.lastname: Jansen
authors.affiliation: Academic Collaborative Centre for Public Health Limburg, Public Health Service Southern Limburg, Geleen, The Netherlands.
authors.forename: D C L
authors.initials: DC
authors.lastname: Mohren
authors.affiliation: Academic Collaborative Centre for Public Health Limburg, Public Health Service Southern Limburg, Geleen, The Netherlands; Department of Health Services Research, CAPHRI School for Public Health and Primary Care, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
authors.forename: M W J
authors.initials: MW
authors.lastname: Jansen
authors.affiliation: Department of Epidemiology, CAPHRI School for Public Health and Primary Care, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands.
authors.forename: I J
authors.initials: IJ
authors.lastname: Kant
mesh_terms: D000293:Adolescent; D003430:Cross-Sectional Studies; D003710:Demography; D004644:Emotions; D005260:Female; D006801:Humans; D006948:Hyperkinesis; D008297:Male; D000297:Psychology, Adolescent; D011594:Psychometrics; D057566:Self Report; D012919:Social Behavior; D011795:Surveys and Questionnaires