title: Longitudinal invariance of measurement and structure of global self-concept: a population-based study examining trajectories among adolescents with and without chronic illness.
abstract: OBJECTIVE
  The objectives of this study were to determine whether a measure of global self-concept demonstrated longitudinal measurement invariance between adolescents aged 10-19 years with and without chronic illness and to document differences in their global self-concept trajectories over time.
  
  
  METHODS
  Data were obtained from the National Longitudinal Survey of Children and Youth (N = 10,064). Global self-concept was measured using a scale based on the Self-Determination Questionnaire.
  
  
  RESULTS
  16 percent of adolescents had chronic illness. There was evidence of partial longitudinal invariance in global self-concept between adolescents with and without chronic illness. Controlling for sociodemographic characteristics, adolescents with a chronic illness exhibited lower levels of global self-concept and more precipitous declines over time.
  
  
  CONCLUSIONS
  The results from this study suggest that comparisons of global self-concept between adolescents with and without chronic illness are meaningful and, compared to healthy controls, adolescents with chronic illness are at risk for low global self-concept.
authors.affiliation: Department of Psychiatry and Behavioural Neurosciences, Offord Centre for Child Studies, McMaster University, Chedoke Site, Central Building, Room 310, 1280 Main Street West, Hamilton, Ontario, Canada, L8S 4K1. ferroma@mcmaster.ca
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ferro
authors.forename: Michael H
authors.initials: MH
authors.lastname: Boyle
mesh_terms: D000293:Adolescent; D041923:Adolescent Development / Q000502:physiology*; D000328:Adult; D002170:Canada / Q000453:epidemiology; D002648:Child; D002908:Chronic Disease / Q000453:epidemiology / Q000523:psychology*; D018450:Disease Progression; D005260:Female; D006306:Health Surveys; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012306:Risk; D012649:Self Concept; D055815:Young Adult