Between plurality and proportionality: an analysis of vote transfer systems

The paper considers a general model of electoral systems combining districtbased elections with a compensatory mechanism in order to create any outcome between strictly majoritarian and purely proportional seat allocation. It contains vote transfer and allows for the application of three different correction formulas. Analysis in a two-party system shows that a trade-off exists for the dominant party between its expected seat share and its chance of obtaining majority. Vote transfer rules are also investigated by focusing on the possibility of manipulation. The model is applied to the 2014 Hungarian parliamentary election. Hypothetical results reveal that the vote transfer rule cannot be evaluated in itself, only together with the share of constituency seats. With an appropriate choice of the latter, the three mechanisms may be functionally equivalent.