title: Comparing higher order models for the EORTC QLQ-C30.
abstract: OBJECTIVE
  To investigate the statistical fit of alternative higher order models for summarizing the health-related quality of life profile generated by the EORTC QLQ-C30 questionnaire.
  
  
  METHODS
  A 50% random sample was drawn from a dataset of more than 9,000 pre-treatment QLQ-C30 v 3.0 questionnaires completed by cancer patients from 48 countries, differing in primary tumor site and disease stage. Building on a "standard" 14-dimensional QLQ-C30 model, confirmatory factor analysis was used to compare 6 higher order models, including a 1-dimensional (1D) model, a 2D "symptom burden and function" model, two 2D "mental/physical" models, and two models with a "formative" (or "causal") formulation of "symptom burden," and "function."
  
  
  RESULTS
  All of the models considered had at least an "adequate" fit to the data: the less restricted the model, the better the fit. The RMSEA fit indices for the various models ranged from 0.042 to 0.061, CFI's 0.90-0.96, and TLI's from 0.96 to 0.98. All chi-square tests were significant. One of the Physical/Mental models had fit indices superior to the other models considered.
  
  
  CONCLUSIONS
  The Physical/Mental health model had the best fit of the higher order models considered, and enjoys empirical and theoretical support in comparable instruments and applications.
authors.affiliation: Division of Psychosocial Research and Epidemiology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands.
authors.forename: Chad M
authors.initials: CM
authors.lastname: Gundy
authors.forename: Peter M
authors.initials: PM
authors.lastname: Fayers
authors.forename: Mogens
authors.initials: M
authors.lastname: Groenvold
authors.forename: Morten Aa
authors.initials: MA
authors.lastname: Petersen
authors.forename: Neil W
authors.initials: NW
authors.lastname: Scott
authors.forename: Mirjam A G
authors.initials: MA
authors.lastname: Sprangers
authors.forename: Galina
authors.initials: G
authors.lastname: Velikova
authors.forename: Neil K
authors.initials: NK
authors.lastname: Aaronson
mesh_terms: D016009:Chi-Square Distribution; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis* / Q000534:rehabilitation; D008603:Mental Health; D008960:Models, Psychological; D015233:Models, Statistical; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results