Sincere voting, strategic voting A laboratory experiment using alternative proportional systems

In two laboratory surveys run in France during the 2014 European Elections, we asked the participants to provide their personal evaluations of the parties in terms of ideological proximity, and asked how they would vote under three proportional, closed-list voting rules : the (official) single-vote rule, a split-my-vote rule, and a list-approval rule. The paper analyzes the relation between opinions and vote, under the three systems. Compared to multi-vote rules, the single-vote system leads to voters’ decisions that are more often strategic but also more often sincere. Sincere voting and strategic voting therefore appear to be more consistent than contradictory. Multi-vote rules allow the voter to express complex behavior, and the concepts of “sincere” and “strategic” voting are not always sufficient to render this complexity