Test-retest performance of EQ-5D

Abstract

In order to assess the usefulness of a measure there is a need to determine its measurement (or psychometric) properties. This usually involves examining its reliability (the extent to which the results it provides are reproducible) and its validity (the extent to which it measures what it is intended to measure). The reliability and validity of a measure can be assessed in a number of different ways and the book by Streiner and Norman (1995) provides a readable guide. This chapter reports on the exploration of 1 aspect of reliability, the test-retest reliability or the reproducibility of scores, for the EQ-5D descriptive system and the EQ VAS. Although 2 previous studies have examined the test-retest reliability of health state values elicited using the EQ-5D VAS (Van Agt et al, 1994; Dolan et al, 1994), until now there have been no published findings on the reliability of the EQ-5D descriptive system and the EQ VAS.