Quality of Life Research

, Volume 13, Issue 10, pp 1683–1697

Use of item response theory to develop a shortened version of the EORTC QLQ-C30 emotional functioning scale

  • J.B. Bjorner
  • M.Aa. Petersen
  • M. Groenvold
  • N. Aaronson
  • M. Ahlner-elmqvist
  • J.I. Arraras
  • A. Brédart
  • P. Fayers
  • M. Jordhoy
  • M. Sprangers
  • M. Watson
  • T. Young
Article

DOI: 10.1007/s11136-004-7866-x

Cite this article as:
Bjorner, J., Petersen, M., Groenvold, M. et al. Qual Life Res (2004) 13: 1683. doi:10.1007/s11136-004-7866-x

Abstract

Background: As part of a larger study whose objective is to develop an abbreviated version of the EORTC QLQ-C30 suitable for research in palliative care, analyses were conducted to determine the feasibility of generating a shorter version of the 4-item emotional functioning (EF) scale that could be scored in the original metric. Methods: We used data from 24 European cancer studies conducted in 10 different languages (n=8242). Item selection was based on analyses by item response theory (IRT). Based on the IRT results, a simple scoring algorithm was developed to predict the original 4-item EF sum scale score from a reduced number of items. Results: Both a 3-item and a 2-item version (item 21 ‘Did you feel tense?’ and item 24 ‘Did you feel depressed?’) predicted the total score with excellent agreement and very little bias. In group comparisons, the 2-item scale led to the same conclusions as those based on the original 4-item scale with little or no loss of measurement efficiency. Conclusion: Although these results are promising, confirmatory studies are needed based on independent samples. If such additional studies yield comparable results, incorporation of the 2-item EF scale in an abbreviated version of the QLQ-C30 for use in palliative care research settings would be justified. The analyses reported here demonstrate the usefulness of the IRT-based methodology for shortening questionnaire scales.

Keywords

CancerIRTPalliative carePredictionQuality of LifeShortening of scales

Abbreviations

DIF

differential item functioning

EAP

expected a posteriori

EF

emotional function

EORTC

European Organisation for Research and Treatment of Cancer

IIF

item information function

IRT

item response theory

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • J.B. Bjorner
    • 1
    • 2
    • 14
  • M.Aa. Petersen
    • 3
  • M. Groenvold
    • 3
    • 4
  • N. Aaronson
    • 5
  • M. Ahlner-elmqvist
    • 6
  • J.I. Arraras
    • 7
  • A. Brédart
    • 8
  • P. Fayers
    • 9
    • 10
  • M. Jordhoy
    • 10
  • M. Sprangers
    • 11
  • M. Watson
    • 12
  • T. Young
    • 13
  1. 1.Quality Metric IncorporatedLincolnUSA
  2. 2.National Institute of Occupational HealthCopenhagenDenmark
  3. 3.Department of Palliative Medicine Bispebjerg HospitalCopenhagen
  4. 4.Department of Health services Research, Institute of Public HealthUniversity of Copenhagen Denmark
  5. 5.The Netherlands Cancer InstituteAmsterdam The Netherlands
  6. 6.ENT DepartmentMalmo University Hospital MASMalmoSweden
  7. 7.Department of OncologyHospital of NavarrePamplonaSpain
  8. 8.Institut Curie, Psychiatry and Psycho-Oncology UnitParisFrance
  9. 9.Department of Public HealthAberdeen University Medical SchoolAberdeenUK
  10. 10.Unit of Applied Clinical ResearchThe Norwegian University of Science and Technology (NTNU)TrondheimNorway
  11. 11.Department of Medical Psychology, Academic Medical CenterUniversity of AmsterdamAmsterdamThe Netherlands
  12. 12.Psychological Medicine Royal Marsden NHS Trust Sutton
  13. 13.Lynda Jackson Macmillan CentreMount Vernon HospitalMiddlesexUK
  14. 14.Quality Metric IncorporatedLincolnUSA