title: Measurement equivalence of the newly developed Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55).
abstract: OBJECTIVE
  The aim of this study was to examine measurement equivalence of the newly developed Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55) across age, sex, and time in a representative sample of children with newly diagnosed epilepsy.
  
  
  METHODS
  Data come from 373 children enrolled in the Health-related Quality of Life in Children with Epilepsy Study (HERQULES), a multisite prospective cohort study. Measurement equivalence was examined using a multiple-group confirmatory factor analysis framework, whereby increasingly stringent parameter constraints are imposed on the model. Comparison groups were stratified based on age (4-7 years vs. 8-12 years), sex (male vs. female), and time (measurement of health-related quality of life at diagnosis vs. 24 months later).
  
  
  RESULTS
  The QOLCE-55 demonstrated measurement equivalence at the level of strict invariance for each model tested--age: χ(2) (3,123) = 4,097.3, p < 0.001; Comparative Fit Index (CFI) = 0.968; Root Mean Square Error of Approximation (RMSEA) = 0.042 (0.038, 0.045); sex: χ(2) (3,124) = 4,188.3, p < 0.001; CFI = 0.964; RMSEA = 0.044 (0.040, 0.047); and time: χ(2) (3,121) = 5,185.0, p < 0.001; CFI = 0.965; RMSEA = 0.046 (0.043, 0.048).
  
  
  CONCLUSIONS
  These findings suggest that items comprising the QOLCE-55 are perceived similarly among groups stratified by age, sex, and time and provide further evidence supporting the validity of the scale in children with epilepsy. Health professionals and researchers should be confident that group comparisons made using the QOLCE-55 are unbiased and that any group differences detected are meaningful; that is, not related to differences in the interpretation of items by informants. Future research replicating these findings is encouraged.
authors.affiliation: Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada.|Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada.|Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.|Offord Centre for Child Studies, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Ferro
authors.affiliation: Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada.|Children's Health Research Institute, Lawson Health Research Institute, London, Ontario, Canada.
authors.forename: Shane W
authors.initials: SW
authors.lastname: Goodwin
authors.affiliation: Department of Psychology, Sydney Children's Hospital (Randwick), Randwick, New South Wales, Australia.
authors.forename: Mark
authors.initials: M
authors.lastname: Sabaz
authors.affiliation: Department of Epidemiology and Biostatistics, Western University, London, Ontario, Canada.|Children's Health Research Institute, Lawson Health Research Institute, London, Ontario, Canada.|Department of Paediatrics, Western University, London, Ontario, Canada.
authors.forename: Kathy N
authors.initials: KN
authors.lastname: Speechley
mesh_terms: D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004827:Epilepsy / Q000175:diagnosis* / Q000523:psychology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires / Q000592:standards*
keywords: Epilepsy; Factor analysis; Health-related quality of life; Invariance; Measurement; Rating scales