Campaign Advertising and Election Outcomes

The recent electoral reform in Mexico will surely change the use of TV and radio ads in political campaigns.  Will this make “media effects” larger or smaller?  The Brazilian experience seems to say larger.

By: Bernardo S. da Silveira (Department of Economic, New York University)
João Manoel Pinho de Mello (Department of Economics, PUC-Rio)
Despite the “minimal effects” conventional wisdom, the question of whether campaign advertising influence elections outcome remains open. This is paradoxical because in the absence of a causal link from advertising to candidate performance, it is difficult to rationalize the amounts spent on campaigns in general, and on TV advertising in particular. Most studies using US data, however, suffer from omitted variable bias and reverse causality problems caused by the decentralized market-based method of allocating campaign spending and TV advertising. In contrast with received literature, we explore a quasi-natural experiment produced by the Brazilian electoral legislation, and show that TV and radio advertising has a much larger impact on election outcomes than previously found by the literature. In Brazil, by law, campaign advertising is free of charge and allocated among candidates in a centralized manner. Guber natorial elections work in a runoff system. While in the first round, candidates’ TV and radio time shares are determined by their coalitions’ share of seats in the national parliament, the two most voted candidates split equally TV time if a second round is necessary. Thus, differences in TV and radio advertising time between the first and second rounds are explored as a source of exogenous variation to evaluate the impact of TV advertising on election outcomes. Estimates suggest that a one percentage point increase in TV time causes a 0.241 percentage point increase in votes. Since TV advertising is the most important item in campaign expenditures, this result sheds light on the more general question of the effect of campaign spending on elections outcome.
Keywords: Campaign Expenditures, Election Outcomes, Endogeneity, Quasi-Natural Experiments
JEL: G12 C22 C53 E44