Use of item response theory to develop a shortened version of the EORTC QLQ-C30 emotional functioning scale
Författare
Summary, in English
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.
Avdelning/ar
Publiceringsår
2004
Språk
Engelska
Sidor
1683-1697
Publikation/Tidskrift/Serie
Quality of Life Research
Volym
13
Issue
10
Dokumenttyp
Artikel i tidskrift
Förlag
Springer
Ämne
- Otorhinolaryngology
Nyckelord
- cancer
- IRT
- palliative care
- prediction
- quality of life
- shortening
- of scales
Status
Published
Forskningsgrupp
- Laryngoesophagology, Allergy and Life Quality
ISBN/ISSN/Övrigt
- ISSN: 1573-2649