Voting Systems and Strategic Manipulation: an Experimental Study

This paper presents experiments analyzing the strategic behavior of voters under three voting systems: plurality rule, approval voting, and the Borda count. Strategic behavior is significantly different under each treatment (voting system). Plurality rule leads voters to play in a more sophisticated manner, but not necessarily insincerely, displaying the lowest levels of manipulation. The opposite holds for the Borda count games, where players are the least sophisticated but the most insincere. Approval voting shows intermediate levels of strategic behavior. In terms of social efficiency, plurality rule unexpectedly performs better than both approval voting and the Borda count. Yet, plurality rule is the weakest performer under Condorcet efficiency, whereas approval voting and the Borda count perform remarkably well even with a small electorate. ∗Financial support from Andrew Schotter and the Center of Experimental and Social Sciences at NYU is gratefully acknowledged. I would like to thank Guillaume Frechette, Rebecca Morton, and Andrew Schotter for their constant support and advice. I would also like to thank Steven Brams, Sean Gailmard, and Robert Veszteg for helpful comments. An earlier version of this paper was presented at the 2006 annual meetings of the MPSA and the APSA, at the 2006 Annual Summer Meeting of the Society for Political Methodology and at the 2006 annual meeting of the Economic Science Association. Conference and discussion participants are thanked for useful comments. All errors remain my own. †NYU, Department of Politics, New York, NY, 10012. E-mail address: [email protected].