Rethinking Measurement Equivalence in Comparative Political Research

A growing number of studies test key cultural constructs used in comparative political research for invariance across countries, only to declare these constructs incomparable if the invariance tests fail. The assumption underlying this kind of conclusion is that between-country differences in within-country factor solutions reflect cross-cultural inequivalence of the respective survey items. Using a Bayesian approach, we explore variation in measurement quality across countries focusing on sexual emancipation. We find that between-country differences in factor solutions reflect little more than imbalances in within-country dispersions of the construct items. As we demonstrate, discrete and bounded response scales used in standard surveys enforce a mathematical relationship between extreme country means, low within-country dispersions, and weak factor solutions. We formalize this insight by introducing a between-within model of cultural variation. Our contribution calls into question the practice of declaring constructs to be incomparable based on failed invariance tests.