Establishing the Construct and Predictive Validity of Brief Measures of Affective Polarization

Measuring affective polarization, defined as the liking for one’s political ingroup and dislike for political outgroups, poses methodological challenges in multiparty systems: evaluations of 7, 13, or even more parties in a survey are costly, time consuming and demanding. Studies therefore frequently rely on only a subset of political parties in measures of affective polarization. However, it is unclear how this approach affects the validity of the measurement. Here, we assess the construct and predictive validity of brief affective polarization measures. Across 39 countries, we demonstrate that brief measures that include ratings of only 3-5 parties can maintain acceptable validity, as shown by strong correlations with the full measures and consistent associations with political correlates. The construct and predictive validity of brief measures is best, when selecting a set of large, ideologically diverse parties. We offer specific recommendations on how to effectively capture affective polarization in different multiparty settings.