Thanks, quoted what I think is the relevant methods section below. Various scales, some of which were combined, and then further composited with other scales.
Political orientation was assessed with the single item “What is your political orientation?” on a 1–5 scale ranging from “extremely conservative” to “extremely liberal.” Authoritarianism was measured using 12 items capturing three facets of authoritarianism (subordination, aggression, and conventionalism) from Duckitt, Bizumic, Krauss, and Heled (2010)’s tripartite authoritarianism-conservatism-traditionalism model. Egalitarianism was measured with eight items from Feldman and Steenbergen (2001) and Feldman (1988). Religiousness was assessed with the 9-item religiousness scale created by Koenig, McGue, Krueger, and Bouchard (2005). The scale asks about participation in and frequency of religious activities. 11 items were used to measure socialism liberalism and six measuring fiscal conservatism. These items were adapted from similar questions in the General Social Survey items (Smith, Davern, Freese, & Morgan, 2018). A list of all items for each scale can be found in the supplementary materials of Willoughby, Giannelis, Ludeke, Klemmensen, et al. (2021).
Correlations among our political scales are presented in Table 3. Due to the high correlations among the variables, we create a composite measure to summarise the relationship between intelligence and political opinion. Authoritarianism, egalitarianism, social liberalism and fiscal conservatism scales are combined to create a sum score called the political composite. Before summing, we change the signs of our scales so higher scores indicate left-wing views, ensuring that high composite scores indicate left-wing views too. A scale was coded as being left-wing or right-wing by its correlation with authoritarianism, which is assumed to be right-wing. Example items are shown in Table 2.