Electoral Reform and Parliamentary Debates

• In Event: Understanding Party Cohesion and Legislative Behavior Using Text as Data

Abstract

Electoral rules matter for politics inside legislatures. In this paper, we investigate how parliamentary debates are affected by a change of the electoral system. More specifically, we investigate an electoral reform from a two-round plurality voting single member district system to a multimember proportional system, altered the composition of topics under discussion. We collected the complete record of minutes from the parliament 20 years before and after the reform. Using a structural topic model that group similar debates together into topics, we are able to investigate the effect of the electoral reform on the prevalence of topics debated in the parliament. We find that topics that gave individual MPs credit claiming opportunities were reduced as a result of the reform, while topics that distinguished between parties figured more prominently in the debates.

Authors

• Martin Grødem Søyland, University of Oslo

• Bjorn Hoyland, University of Oslo