Reallocating Wasted Votes in Proportional Parliamentary Elections with ThresholdsDominik Peters

16 April 2026

Dominik Peters (CNRS), 17:15 - 18:45, presents his project in the Interdisciplinary Research Seminar of the GRK "Collective Decision-Making”.

Location: Room 0031, Von-Melle-Park 5 (next to HASPA-Café)

Abstract

In many proportional parliamentary elections, electoral thresholds (typically 3-5%) are used to promote stability and governability by preventing the election of parties with very small representation. However, these thresholds often result in a significant number of “wasted votes” cast for parties that fail to meet the threshold, which reduces representativeness. One proposal is to allow voters to specify replacement votes, by either indicating a second choice party or by ranking a subset of the parties, but there are several ways of deciding on the scores of the parties (and thus the composition of the parliament) given those votes. We introduce a formal model of party voting with thresholds, and compare a variety of party selection rules axiomatically, and experimentally using a dataset we collected during the 2024 European election in France. We identify three particularly attractive rules, called Direct Winners Only (DO), Single Transferable Vote (STV) and Greedy Plurality (GP).

Find the abstract as PDF here.