Modelling Ordinal Electoral Systems: The Uniqueness of South Australian Legislative Elections

Understanding the relationship between voting methods and electoral outcomes is one of the central challenges of electoral systems research. In the case of ordinal voting systems, theory and empirical models directly conflict as to whether particular ordinal voting methods significantly affect electoral outcomes. This conflict is partially due to the lack of a model that can simulate real legislative elections reliably enough to empirically test theoretical claims. In this research note, the authors argue that South Australian lower house elections constitute a unique legislative case where sufficient data are publicly available to generate such a model. They then describe the new model and critically examine its accuracy and limitations. They conclude that their model is sufficiently robust to form a basis for future research into the impact of ordinal voting systems on outcomes in legislative elections.