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

Research output: Contribution to journalArticle

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.

Details

Authors
  • JB Bjorner
  • MA Petersen
  • M Groenvold
  • N Aaronson
  • Marianne Ahlner-Elmqvist
  • JI Arraras
  • A Bredart
  • P Fayers
  • M Jordhoy
  • M Sprangers
  • M Watson
  • T Young
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Otorhinolaryngology

Keywords

  • cancer, IRT, palliative care, prediction, quality of life, shortening, of scales
Original languageEnglish
Pages (from-to)1683-1697
JournalQuality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation
Volume13
Issue number10
Publication statusPublished - 2004
Publication categoryResearch
Peer-reviewedYes