Today, electoral systems are one of the most prolifically studied subjects of political science. The field dates back to Maurice Duverger’s (1973 [1954]) well-known work "Les partis politiques", in which he proposed that single member district plurality rules tend to generate two-party systems. This ‘sociological law’ was tested and refined with cross-national data by Rae’s (1967) "Political Consequences of Electoral Laws". Since then, multiple studies contributed to a vast body of literature on the macro outcomes of electoral laws such as the number of parties and proportionality (e.g. Lijphart 1994, Taagepera & Shugart 1989). Beyond, also the micro dimension of the relationship – such as the behavior of voters, candidates, party leaders etc. – was analyzed by numerous political scientists (e.g. Cox 1997).


Despite the substantial evidence accumulated by traditional as well as by recent literature, a number of methodological complexities constrain the evaluation of the findings: First of all, one of the major problems of previous studies of electoral system concerns endogenity. Several scholars argue that the direction of causality flows in the opposite direction claiming that electoral system change is rather a consequence than a cause. Secondly, cross-sectional studies face the problem of controlling for all outcomes and outputs. A third problem is related to omitted variable bias. And finally, it has proved rather difficult to specify a model that accounts for time trends.


It is the aim of our project to contribute to a solution of these methodological complexities as our analyses do not concentrate on the consequences of electoral laws per se but on the effects of electoral system change. When research identifies empirical political consequences of electoral systems, these effects should be particularly distinct when countries change their electoral laws. In this context, the project mainly focuses on three politically relevant factors that are thought to be affected by electoral system change: i) the size and composition of party systems; ii)  political representation and iii) the overall level of democratic quality. Thereby, the project will not only concentrate on the national-level dynamics but move beyond in order to gain insight on the dynamics of the relationships on the subnational level as well as on the individual level.


Therefore, apart from the substantive dimension, one fundamental aspect of the project will revolve around the collection of data depicting electoral institutions and their consequences at the national level, the electoral districts, and on the individual level in advanced industrial democracies. Quantitative comparative analyses of this extensive data will allow us to re-examine the robustness of established assumptions of electoral research and to contribute to the vast body of literature on electoral systems. Moreover, the project seeks to provide new insights for engineers of electoral rules.



Cox, Gary W. 1997: 'Making Votes Count. Strategic Coordination in the World's Electoral Systems', Cambridge: Cambridge University Press.

Duverger, Maurice 1973: 'Les partis politiques', 8. Auflage. Paris: Armand Colin.

Lijphart, Arend 1994:' Electoral Systems and Party Systems', Oxford: Oxford University Press.

Rae, Douglas W. 1967: 'The Political Consequences of Electoral Laws', Revised. Ed. New Haven: Yale University Press.

Taagepera, R. & Shugart, M. 1989: 'Seats and votes:The effects and determinants of electoral systems', New Haven, CT: Yale University Press.