Format

Send to

Choose Destination
See comment in PubMed Commons below
Qual Life Res. 2008 Apr;17(3):463-73. doi: 10.1007/s11136-008-9318-5. Epub 2008 Mar 5.

Quantification of the level descriptors for the standard EQ-5D three-level system and a five-level version according to two methods.

Author information

1
Public Health Epidemiology, Department of Social Medicine, Academic Medical Center, PO Box 22660, Amsterdam, DD 1100, The Netherlands. m.f.janssen@amc.uva.nl

Abstract

OBJECTIVES:

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.

METHODS:

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?).

RESULTS:

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.

DISCUSSION:

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.

PMID:
18320352
PMCID:
PMC2275305
DOI:
10.1007/s11136-008-9318-5
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Springer Icon for PubMed Central
    Loading ...
    Support Center