Functional equivalence and validity of religiousness indicators in cross-cultural comparative surveys

Abstract

Cross-cultural comparative surveys have become an important tool to investigate social attitudes across different countries. However, this methodology is confronted with a number of challenges. One of the core problems is the functional equivalence of the concepts and indicators used. In this article, we study this problem in regard to the investigation of religiousness in three prominent surveys, the World Value Survey, the International Social Survey Programme, and the Religion Monitor. Our contribution starts with the fundamental question of the intercultural meaning of single items that are commonly used for the measurement of religiosity. From the comparison of the linguistic formulation of these items in different languages and across the three surveys, we obtain evidence of whether the concept of religiousness has the same meaning in different countries and to what extent the results depend on the formulation of the item. Subsequently, we use confirmatory factor analysis to test whether two religiousness scales derived from the International Social Survey Programme are structurally equivalent across countries. In the final step, we proceed to a substantive analysis, comparing religiousness scales from the three surveys in order to examine to what extent scales that claim to measure the same construct in fact produce similar results when applied to different countries. Our findings suggest that the paradigm of "asking the same questions" is difficult to apply and problematical with respect to some core indicators of individual religiousness and that questionnaires that are based on the Western concept of religion will lead to biased results when applied to worldwide cross-cultural comparison.