Assessing the empirical validity of alternative multi-attribute utility measures in the maternity context

Table 5 Efficiency of multi-attribute utility measures to detect differences in self-reported health status; women for whom both utility scores were between 0.296 and 1.0 (n = 481)

Measure	Categorisation of self-reported health status	Utility score		t-test^a		Relative efficiency^b	ROC curve
		Mean	(SD)	t -statistic	p -value		Area ^c	95% CI
EQ-5D	Excellent	0.964	(0.085)	8.682	<0.001	1.000	0.712*	(0.655, 0.768)
	Very good, good, fair or poor	0.861	(0.137)
SF-6D	Excellent	0.916	(0.091)	10.038	<0.001	1.337	0.792*	(0.741, 0.844)
	Very good, good, fair or poor	0.794	(0.129)
EQ-5D	Excellent or very good	0.931	(0.103)	10.029	<0.001	1.000	0.747*	(0.699, 0.795)
	Good, fair or poor	0.804	(0.143)
SF-6D	Excellent or very good	0.876	(0.106)	13.816	<0.001	1.898	0.835*	(0.797, 0.872)
	Good, fair or poor	0.725	(0.114)
EQ-5D	Excellent, very good or good	0.897	(0.124)	8.672	<0.001	1.000	0.829*	(0.763, 0.896)
	Fair or poor	0.716	(0.126)
SF-6D	Excellent, very good or good	0.833	(0.123)	9.663	<0.001	1.242	0.834*	(0.775, 0.894)
	Fair or poor	0.661	(0.105)
EQ-5D	Excellent, very good, good or fair	0.882	(0.134)	6.482	0.018	1.000	0.720	(0.471, 0.970)
	Poor	0.678	(0.053)
SF-6D	Excellent, very good, good or fair	0.818	(0.l30)	10.121	0.006	2.438	0.770*	(0.544, 0.997)
	Poor	0.583	(0.039)

SD denotes standard deviation. ROC denotes receiver operating characteristic. CI denotes confidence interval.
^a Not assuming equality of variance as Levene test showed statistically significant differences in variances between self-reported health status groups.
^b Relative efficiency statistic is referenced to 1.0 for the EQ-5D measure. A value higher than 1.0 indicates that the SF-6D is more efficient than the EQ-5D in detecting differences between women in terms of their self-reported health status.
^c Area under receiver operating characteristic (ROC) curves; * p < 0.05 indicates that area under the ROC curve was statistically significantly greater than 0.5 and that measure has discriminatory power.

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