title: Testing the measurement equivalence of paper and interactive voice response system versions of the EORTC QLQ-C30.
abstract: OBJECTIVE
  The objective of this study was to evaluate the measurement equivalence of an interactive voice response system (IVRS) version and the original paper-based version of the EORTC QLQ-C30.
  
  
  METHODS
  The QLQ-C30 is a cancer-specific, health-related quality of life questionnaire consisting of nine multi-item scales (physical, role, emotional, cognitive and social functioning, fatigue, nausea/vomiting, pain, and quality of life) and six single item measures (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial problems). This study utilized a crossover design with subjects randomly assigned to one of two assessment orders: (1) paper then IVRS or (2) IVRS then paper. Equivalence between the two administration modes was established by comparing the 95% lower confidence interval (CI) of the intraclass correlation coefficients (ICCs) for each scale, with a critical value of 0.70.
  
  
  RESULTS
  The ICCs for the nine multi-item scales were all above 0.79, ranging from 0.791 to 0.899 (ICC 95% lower CI range 0.726-0.865) and significantly different from our threshold reliability of 0.70. The ICCs for the six single items ranged from 0.689 to 0.896 (ICC 95% lower CI range 0.611-0.888). Two of the items, insomnia and appetite loss, were not statistically different from 0.70. When considered together, the per-protocol analysis results support the equivalence of the paper and IVRS versions of the QLQ-C30 for 13 of the 15 scores.
  
  
  CONCLUSIONS
  This analysis provides evidence that the scores obtained from the IVRS version of the QLQ-C30 are equivalent to those obtained with the original paper version except for the insomnia and appetite loss items.
authors.affiliation: Patient-Reported Outcome Consortium, Critical Path Institute, 1730 E River Road, Tucson, AZ, 85718-5893, USA, jlundy@c-path.org.
authors.forename: J Jason
authors.initials: JJ
authors.lastname: Lundy
authors.forename: Stephen Joel
authors.initials: SJ
authors.lastname: Coons
authors.forename: Neil K
authors.initials: NK
authors.lastname: Aaronson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001130:Arizona; D018592:Cross-Over Studies; D004192:Discrimination, Psychological; D005260:Female; D014943:Global Health; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis / Q000523:psychology* / Q000628:therapy; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010209:Paper; D011788:Quality of Life; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D049250:Speech Recognition Software; D011795:Surveys and Questionnaires; D055815:Young Adult