Designing districts for new PR systems

Abstract This chapter examines district design in newly adopted proportional representation (PR) systems. Building on the electoral geography literature and emphasizing differences in district magnitude, we develop a theoretical argument on how the composition of reform coalitions influences district design in newly adopted PR systems. We expect parties with comparatively concentrated voter bases to try to create high entry barriers for other parties in these regions. Such parties design a large number of districts with low magnitude and oppose mergers with ideologically heterogeneous districts. By sheltering locally dominant parties from competition, these districts inherit some of the distorting features of the previous majoritarian representation (MR) systems. In contrast, parties with comparatively dispersed voter bases try to reduce entry barriers. Such parties push for large districts that guarantee the proportional translation of votes into seats, thus allowing them to win seats despite their dispersed voter bases.