In most religions, the preservation of one’s own, God-given, life is considered obligatory, while the time trade-off method (TTO) forces one to voluntarily forego life years. We sought to verify how this conflict impacts TTO-results among the religious.
We used the data from the only EQ-5D valuation in Poland (2008, three-level, 321 respondents, 23 states each)—a very religious, mostly Catholic country. We measured the religiosity with the belief in afterlife question on two levels: strong (definitely yes) and some (also rather yes), both about a third of the sample.
The religious more often are non-traders, unwilling to give up any time in exchange for quality of life: odds ratio (OR) equal to 1.97 (strong religiosity), OR 1.55 (some religiosity); and less often consider a state worse than death: OR 0.67 (strong), OR 0.81 (some). These associations are statistically significant (\(p^*<0.001\)) and hold when controlling for possible demographic confounders. Strong religiosity abates the utility loss: in the additive approach by 0.14, in the multiplicative approach by the factor of 2.1 (both \(p^*<0.001\)), especially among the older. Removing the effect of religiosity from the value set reduces the utility by 0.05 on average.
The results may stem from a true difference in preferences or be a TTO-artifact and would vanish for other elicitation methods. Juxtaposing our findings with comments from respondents in other studies suggests the latter. Therefore, this Weltanschauung effect should be removed in cost–utility analysis.