Relaxing measurement invariance in cross-national consumer research using a hierarchical IRT model

With the growing interest of consumer researchers to test measures and theories in an international context, the cross-national invariance of measurement instruments has become an important issue. At least two issues still need to be addressed. First, the ordinal nature of the rating scale is ignored. Second, when few or no items in the confirmatory factor analysis (CFA) exhibit metric and scalar invariance across all countries, comparison of results across countries is difficult. We solve these problems using a hierarchical IRT model. An empirical application is provided for susceptibility to normative influence, using a sample of 5,484 respondents from 11 countries on four continents.