Working Paper: NBER ID: w18986
Authors: Chad Kendall; Tommaso Nannicini; Francesco Trebbi
Abstract: Rational voters update their subjective beliefs about candidates' attributes with the arrival of information, and subsequently base their votes on these beliefs. Information accrual is, however, endogenous to voters' types and difficult to identify in observational studies. In a large scale randomized trial conducted during an actual mayoral campaign in Italy, we expose different areas of the polity to controlled informational treatments about the valence and ideology of the incumbent through verifiable informative messages sent by the incumbent reelection campaign. Our treatments affect both actual vote shares at the precinct level and vote declarations at the individual level. We explicitly investigate the process of belief updating by comparing the elicited priors and posteriors of voters, finding heterogeneous responses to information. Based on the elicited beliefs, we are able to structurally assess the relative weights voters place upon a candidate's valence and ideology. We find that both valence and ideological messages affect the first and second moments of the belief distribution, but only campaigning on valence brings more votes to the incumbent. With respect to ideology, cross-learning occurs, as voters who receive information about the incumbent also update their beliefs about the opponent. Finally, we illustrate how to perform counterfactual campaigns based upon the structural model.
Keywords: voting behavior; campaign information; randomized trial
JEL Codes: H1; H7
Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.
| Cause | Effect |
|---|---|
| Informing voters about the valence of the incumbent (D72) | Increases support for the incumbent (D79) |
| Campaigning on valence (D79) | Outperforms campaigning on ideology (D72) |
| Receiving information about the incumbent (D83) | Updates beliefs about the opponent (D83) |
| Valence treatments (D46) | Effective in changing votes (D72) |
| Both valence and ideological messages (D46) | Significantly alter voters' beliefs about both candidates (D79) |