Under evaluative voting, the voter freely grades each candidate on a numerical scale, with the winning candidate being determined by the sum of the grades they receive. This paper compares evaluative voting with the two-round system, reporting on an experiment which used various evaluation scales, conducted during the first round of the 2012 French presidential election. Invitations to participate in the study were extended to around 5,000 voters in three cities, and the experiment attracted 2,340 participants. Basing our argument on the * We extend grateful thanks to all the members of the Community Councils, all the participants, and all the volunteers who helped us on April 22.(See http://www.gate.cnrs.fr/spip.php?rubrique94#Merci).† GATE L-SE (UMR CNRS 5824), University Jean Monnet, 42 000 Saint-Etienne, France, antoinette.baujard@univ-st-etienne.fr ‡ CREM (UMR CNRS 6211), University of Caen Basse-Normandie, 14 000 Caen, France, frederic.gavrel@unicaen.fr § CNRS and Beta (UMR CNRS 7522), University of Strasbourg, 67 085 Strasbourg,France, igersheim@unistra.fr ¶ PREG (UMR CNRS 7176), Ecole polytechnique, 91 128 Palaiseau, France, jeanfrancois.laslier@polytechnique.edu CREM (UMR CNRS 6211), University of Caen Basse-Normandie, 14 000 Caen, France isabelle.lebon@unicaen.fr 1 ranks, relative scores, and grade profiles of candidates, we show that the two-round system favors "exclusive" candidates, that is candidates who elicit strong feelings, while evaluative rules favor "inclusive" candidates, that is candidates who attract the support of a large span of the electorate. These differences are explained by two complementary reasons: the opportunity for the voter to support several candidates under evaluative voting rules, and the specific pattern of strategic voting under the official, two-round voting rule.
Classification JEL: D72, C93Keywords: Voting, In Situ Experiment, Evaluative Voting, Approval Voting, Two-round system
Highlights• The two-round system favors "exclusive" candidates, that is candidates who elicit strong feelings.• Evaluative rules favor "inclusive" candidates, that is candidates who attract the support of a large span of the electorate.• One explanation of the differences between the elections wins and rankings between the two-round system and evaluative voting rules is that the opportunity for the voter to support several candidates under evaluative voting rules.• One explanation of the differences between the elections wins and rankings between the two-round system and evaluative voting rules relies in the specific pattern of strategic voting under the official, two-round voting rule.
2A voting rule is supposed to be able to determine the candidate most favored by a community of voters. However, it is a well-established conclusion of social choice theory that voting by itself is mathematically incapable of picking the single and uncontroversial winner of an election (Arrow 1957).For a given set of electoral preferences, different voting rules may elect or favor distinct candidates (F...