The validity and reliability of EQ-5D health state valuations in a survey of Maori

This note reports on a 2000 study of the content validity of the EQ-5D's representation of health for 66 Maori (New Zealand's indigenous people, comprising 14.5% of the population) accessed through cultural networks. Also examined was the construct validity of the health state valuation instrument and its test-retest reliability based on repeated valuations for the two extreme health states. The possibility that the EQ-5D fails to capture what Maori regard as 'health' derives from the so-called 'Maori health model' that augments biological health with mental, spiritual and family well-being. Seventy six percent of respondents considered the EQ-5D's representation of health to be adequate. This proportion is not statistically significantly different from the rates for non-Maori and Maori respectively in an earlier study and might suggest the EQ-5D has content validity for Maori. However, the high prevalence of missing valuations, particularly for dead, and logical inconsistencies suggests that the health state valuation instrument lacks construct validity, although there is evidence of test-retest reliability.