Dear Candidates, Campaign on Your Valence, Not Your Ideology

Campaigning on the candidates' valence – rather than their ideology - brings more votes to politicians during elections. This is what Tommaso Nannicini (Department of Economics) and co-authors have found in their study on a large randomized campaign: in their forthcoming American Economic Review article, How Do Voters Respond to Information? Nannicini, Chad Kendall and Francesco Trebbi (both from University of British Columbia) studied the campaign of an Italian incumbent mayor in a medium-sized Italian city, Arezzo, by administering randomized messages about the candidate's valence and/or ideology. This was the first time a real-world politician accepted to randomize the content of the electoral messages in the campaign at large. The results of the study confirmed the impact of campaigning information on both voters' choices and beliefs, while showing more significant effect for campaigning on valence than ideology.

To run the randomized controlled experiment, the authors randomly divided the city into four areas and had the incumbent mayor send different messages by both direct mail (to 100% of families) and through phone calls (to 25% of families) a week before the election day. While voters in the first area received information on valence, in the second area they received information on ideology. In the third area voters received information on both and finally voters in the fourth area did not receive any information. The informational treatments were administered by the incumbent as part of his campaign.

Surveys were administered on the eligible voters before and after the provision of campaigning information. They were designed to capture individual voters' beliefs about valence and ideology with respect to both the incumbent and the main challenger. Moreover, the statistical methodology provides a fairly good approximation of the way voters process their information.

Employing such statistical framework, the researchers show that while messages about valence positively impacted the number of votes earned by the incumbent, information on ideology had an impact only on voters' beliefs but not on their choices in the electoral ballot. Moreover, the results support the hypothesis that campaign information affects not only voters' beliefs about the candidate originating the message, but also their beliefs about the opponent.