Replication Data for: Informed Preferences? The Impact of Unions on Workers' Policy Views

Despite declining memberships, labor unions still represent large shares of electorates worldwide. Yet their political clout remains contested. To what extent, and in what way, do unions shape workers’ political preferences? We address these questions by combining unique survey data of American workers and a set of inferential strategies that exploit two sources of variation: the legal choice that workers face in joining or opting out of unions and the over-time reversal of a union’s policy position. Focusing on the issue of trade, we offer evidence that unions influence their members’ policy preferences in a significant and theoretically predictable manner. In contrast, we find that self-selection into membership accounts at most for a quarter of the observed “union effect”. The study illuminates the impact of unions in cohering workers’ voice and provides insight on the role of information provision in shaping how citizens form policy preferences.