Quality of Life Research

, Volume 8, Issue 1–2, pp 25–43 | Cite as

Assessing the consistency of psychometric properties of the HRQoL scales within the EORTC QLQ-C30 across populations by means of the Mokken Scaling Model

  • K. Ringdal
  • G. I. Ringdal
  • S. Kaasa
  • K. Bjordal
  • F. Wisløff
  • S. Sundstrøm
  • M. J. Hjermstad


This paper demonstrates how the Mokken Scaling Model and other statistical tools may be useful in assessing the consistency of psychometric properties of health-related quality of life (HRQoL) scales across various populations. The main focus is the psychometric performance of the scales proposed for the EORTC QLQ-C30 in seven patient groups totalling more than 2,000 cancer patients. All scales performed satisfactorily in the total sample with the exception of the role functioning and cognitive functioning scales, which failed in terms of reliability and item discriminant validity. The descriptive statistics for the scales show that several of them, particularly those that build upon only two items, have discrimination problems at the extremes, visible in the high percentages at the maximum or the minimum observed values. The scalability analysis in the subsamples showed that the essential assumption in the Mokken Scaling Model of equal item step order does not hold for the cognitive functioning, emotional functioning and physical functioning scales. We conclude that the Mokken Scaling Model is well suited to the purpose of examining the generalizability of HRQoL scales across subpopulations although a global statistical test of the fit of the measurement model is not available.

Mokken Scaling Model psychometric properties in subpopulations HRQoL quality of life EORTC QLQ-C30. 


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Copyright information

© Chapman and Hall 1999

Authors and Affiliations

  • K. Ringdal
    • 1
  • G. I. Ringdal
    • 2
  • S. Kaasa
    • 3
  • K. Bjordal
    • 4
  • F. Wisløff
    • 1
  • S. Sundstrøm
    • 4
  • M. J. Hjermstad
    • 5
    • 6
  1. 1.Departments of Sociology and Political ScienceNorwegian University of Science and TechnologyDragvollNorway
  2. 2.Department of PsychologyNorwegian University of Science and TechnologyDragvollNorway
  3. 3.Palliative Medicine Unit and Unit for Epidemiology and Clinical Research, Faculty of MedicineNorwegian University of Science and Technology, Trondheim University HospitalTrondheimNorway
  4. 4.Department of Medical Oncology and RadiotherapyNorwegian Radium HospitalOsloNorway
  5. 5.Department of HematologyUllevål HospitalOsloNorway
  6. 6.Norwegian Radium Hospital and Norwegian Cancer SocietyOsloNorway

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