Where Minorities are the Majority: Electoral Rules and Ethnic Representation

The impact of electoral rules on descriptive representation has generated a large body of work focused primarily on gender and secondarily on ethnicity. While others have suggested the importance of social group size and dispersion, this study offers a parsimonious and formalized theory centered on these factors to explain varying representation across institutions for different social groups. The theory is confirmed analytically in an idealized political system and probed with simulations that test a complete set of counterfactuals. We then test these ideas empirically with a new, large dataset composed of mixed electoral system elections from around the world, and finally with country studies of individual elections in Russia and New Zealand. We find that multimember districts provide better representation than single-member districts only for geographically dispersed social groups that are large, but not too large, as a voting bloc (i.e., for women, understood as a group and a few ethnicities globally). Since most minority ethnic groups are concentrated in a particular region, district magnitude has little impact on their representation. In sum, we formalize long-standing hypotheses regarding the role of geography for institutions, confirm this relationship after creating the largest data on mixed systems so far available, and probe mechanisms in country studies across varied electoral contexts.