In latent scaling applications, such as the positioning of political parties, differential item functioning (DIF) may occur because of measurement issues or because of substantive differences in the association between latent and manifest variables. While the first source of DIF has received considerable attention, the second has not, although it is of potential interest to comparative scholars. In this research note, we introduce a novel hierarchical Bayesian item response model that allows us to disentangle different sources of DIF. Drawing on the 2019 Chapel Hill Expert Survey (CHES), we highlight how the same issues are unequally politicized across Western Europe, and how some issues are less ideologically determined than others. Our model can be adapted to alternate settings, allowing researchers to shine a light on variation in, e.g., ideology, issue politicization, or party competition.

To date, the statistical software designed for assessing differential item functioning (DIF) with Mantel-Haenszel procedures has employed the following statistics: the Mantel-Haenszel chi-square statistic, the generalized Mantel-Haenszel test and the Mantel test. These statistics permit detecting DIF in dichotomous and polytomous items, although they limit the analysis to two groups. On the contrary, this article describes a new approach (and the related software) that, using the generalized Mantel-Haenszel statistic proposed by Landis, Heyman, and Koch (1978), permits DIF assessment in multiple groups, both for dichotomous and polytomous items. The program is free of charge and is available in the following languages: Spanish, English and Portuguese.

Loneliness is experienced in many cultures. To properly assess cross-cultural differences, attention should be paid to the level, determinants, and measurement of loneliness. However, cross-cultural studies have rarely taken into account more than one of these. Differences in the level of loneliness were hypothesized on the basis of national differences in partnership, kinship, and friendship, which were assumed to be related to cultural standards within a society. Differences were examined among married and widowed older adults aged 70 to 89 years living independently in the Netherlands (N = 1,847), Tuscany, Italy (N = 562), and Manitoba, Canada (N = 1,134). Loneliness was measured with an 11-item scale. The Manitobans were high on emotional loneliness and the Tuscans were high on social loneliness. Partner status excepted, the determinants were nearly the same across the three locations. Differential item functioning (DIF) related to the three locations was observed for most items. Interactions with gender and the availability of a partner relationship were observed.