Quantification of the level descriptors for the standard EQ-5D three-level system and a five-level version according to two methods
- M. F. JanssenAffiliated withPublic Health Epidemiology, Department of Social Medicine, Academic Medical CenterEuroQol Group Email author
- , E. BirnieAffiliated withPublic Health Epidemiology, Department of Social Medicine, Academic Medical CenterInstitute of Health Policy and Management
- , G. J. BonselAffiliated withPublic Health Epidemiology, Department of Social Medicine, Academic Medical CenterEuroQol GroupInstitute of Health Policy and Management
Our aim was to compare the quantitative position of the level descriptors of the standard EQ-5D three-level system (3L) and a newly developed, experimental five-level version (5L) using a direct and a vignette-based indirect method.
Eighty-two respondents took part in the study. The direct method represented a visual analog scale (VAS) rating of the nonextreme level descriptors for each dimension and each instrument separately. The indirect method required respondents to score 15 health scenarios with 3L, 5L and a VAS scale. Investigated were: (1) equidistance (Are 3L and 5L level descriptors distributed evenly over the VAS continuum?); (2) isoformity (Do the identical level descriptors on 3L and 5L yield similar results?); and (3) consistency between dimensions (Do the positions of similar level descriptors differ across dimensions within instruments?).
Equidistance without transformation was rejected for all dimensions for both 3L and 5L but satisfied for 5L after transformation. Isoformity gave mixed results. Consistency between dimensions was satisfied for both instruments and both methods.
The level descriptors have similar distributions across comparable dimensions within each system, but the pattern differs between 3L and 5L. This methodological study provides evidence of increased descriptive power and a broadened measurement continuum that encourages the further development of an official five-level EQ-5D.
KeywordsEQ-5D Methodology Health-related quality of life Psychometrics Health status
- Quantification of the level descriptors for the standard EQ-5D three-level system and a five-level version according to two methods
- Open Access
- Available under Open Access This content is freely available online to anyone, anywhere at any time.
Quality of Life Research
Volume 17, Issue 3 , pp 463-473
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- Springer Netherlands
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- Health-related quality of life
- Health status
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- Author Affiliations
- 1. Public Health Epidemiology, Department of Social Medicine, Academic Medical Center, P.O. Box 22660, Amsterdam, DD 1100, The Netherlands
- 2. EuroQol Group, Amsterdam, The Netherlands
- 3. Institute of Health Policy and Management, Erasmus MC, Rotterdam, The Netherlands