What Do We Measure When We Measure Affective Polarization across Countries?

Measures of affective polarization-that is, dislike and hostility across party lines-have been developed and validated in the context of America's two-party system. Yet increasingly, affective polarization is examined comparatively. We address this issue by introducing a novel dataset that measures aspects of partisan affect in 10 countries with diverse party systems. We detect associations between partisan affect toward out-parties versus affect toward out-parties' supporters, but their strength varies across countries. We discuss measurement reasons for this variation and consider the implications of our findings for the emerging comparative affective polarization literature.