Proportional Representation

Normative Expectations

In normative terms, defenders of proportional representation refer to the following advantages: (a) maximal representation of all opinions and interests in parliament in relation to the percentage of votes in their favor; (b) rejection of excessively artificial political majorities that do not correspond to any real majority in the electorate; (c) promotion of majorities by negotiation, compromise, and consent; (d) prevention of extreme political convulsions in the composition of parliament caused by the distortion effect of the electoral system rather than by fundamental changes in the voters' political preferences; (e) equality of the vote not only in numerical but in outcome terms (effective vote). All these advantages may be aggregated in the PR ideal of “fair representation.” Nevertheless, the PR ideal continues to be seriously challenged by the opposite principle of representation. But empirically, real PR systems deviate more or less from it.

Diversity of Proportional Systems

There are many ways of designing a PR system, especially with regard to increasing or decreasing [Page 662]proportional effects. The achievement of proportionality is mainly dependent on districting, thresholds, and electoral formulae. In a nationwide district, proportionality is nearly accurate (pure PR). Distortions between the share of votes and the share of seats increase when magnitudes of districts decrease. Theoretically, the amount of disproportionality in the national outcome is highest in single-member districts. Thresholds, used in order to prevent an excessive fragmentation of parliaments, force political parties to show a certain level of electoral support (for example, 5% of the votes) for getting parliamentary seats. Their effects on proportionality differ. While pure PR encourages dispersion of votes by strategic mistakes, leading to high numbers of wasted votes (up to 30%), thresholds may exert a concentration effect on voting behavior that fosters the number of effective votes and by this a higher degree of proportionality. The most common PR system provides for multimember districts of different magnitudes with blocked lists, using the d'Hondt formula.

Empirical Evidence

Proportional representation has been long discredited for creating multiparty systems and political instability. However, most stable democracies of the world apply PR systems. Nearly all of them use technical elements to prevent extreme fragmentation. Furthermore, PR systems may create a considerable distortion in the vote–seat relation. To be true, real effects of PR on party systems crucially depend on contextual factors, which are also responsible for the kind of electoral system in force. In general, there is no linear causal relationship between PR and party system.

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