The true significance of ‘high’ correlations between EQ-5D value sets
Ombler, Franz; Albert, Michael; Hansen, Paul

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Ombler, F., Albert, M., & Hansen, P. (2017). The true significance of ‘high’ correlations between EQ-5D value sets (Economics Discussion Papers Series No. 1704). University of Otago. Retrieved from http://hdl.handle.net/10523/7247
Permanent link to OUR Archive version:
http://hdl.handle.net/10523/7247
Abstract:
High correlation coefficients for EQ-5D value sets derived from different samples, e.g. across countries, are conventionally interpreted as evidence that the people in the respective samples have similar health-related quality of life preferences. However, EQ-5D value sets contain many inherent rankings of health state values by design. By calculating coefficients for value sets created from random data, we demonstrate that ‘high’ correlation coefficients are an artefact of these inherent rankings; e.g. median Pearson’s r = 0.783 for the EQ-5D-3L and 0.850 for the EQ-5D-5L instead of zero. Therefore, high correlation coefficients do not necessarily constitute evidence of ‘true’ associations. After calculating significance levels based on our simulations – available as a resource for other researchers – we find that many high coefficients are not as significant as conventionally interpreted, whereas other coefficients are not significant. These ‘high’ but insignificant correlations are in fact spurious.
Date:
2017-03
Publisher:
University of Otago
Series number:
1704
ISSN:
1178-2293
Keywords:
Correlation; statistical significance; EQ-5D; health-related quality of life
Research Type:
Discussion Paper
Languages:
English
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- Economics [316]
- Discussion Paper [439]
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