IPP Policy Brief n°40 - May 2019

Expressive voting and its costs

IPP Policy Brief n°40

May 2019

Authors : Vincent Pons, Clémence Tricaud, Vestal McIntyre

Contact : vpons@hbs.edu


logo-pdf-minExpressive voting and its costs




Voters who support a candidate with little or no chance of winning face a choice: whether to express their true preference, vote for their preferred candidate, and risk wasting their vote; or vote strategically for a second-best candidate who is more likely to be in a position to win.

To explore this tradeoff, this study focuses on French parliamentary and local elections, in which the top two candidates always qualify for the second round, and others also qualify if they get a number of voters higher than 12.5 percent of registered citizens. Results show that third candidates who qualify for the second round tend to prefer staying in the race rather than dropping out. Many of the third candidates’ supporters then act expressively and vote for them instead of their second-best candidate among the top two. The study finds this disproportionally harms the candidate ideologically closest to the third and often causes their defeat. This behavior by voters and candidates likely affects the results of many elections beyond those in the study, including European elections and other proportional elections, where voters face similar trade-offs.

The results call for ideologically similar parties to reach agreements limiting the number of candidates or lists that are competing, and for the adoption of voting systems in which electoral outcomes are less distorted by voters’ and candidates’ failure to act strategically.

Key points:

  • The presence of a third candidate in the second round of French parliamentary and local elections increases the share of people casting a ballot for any of the candidates by 7.8 percentage points and decreases the vote share of the top two candidates by 6.9 percentage points.
  • •It disproportionately harms the top-two candidate ideologically closest to the third, and causes their defeat in 19.2 percent of the races.
  • While voting expressively has the starkest costs in plurality elections, it also has costs in proportional ones such as regional or European elections.
  • The study calls for ideologically similar parties to reach agreements limiting the number of candidates that are competing to avoid dividing their votes, and calls into question the widespread use of the plurality rule as an effective method to aggregate votes to reflect citizen preferences.

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