Media Coverage, Advertising, and Electoral Volatility: The Crucial Role of Party Competence

This paper aims to clarify the mechanism linking media coverage and advertising to electoral volatility. It is argued that the link is indirect rather than direct: Parties' communication affects electoral volatility because it alters citizens' perceptions of party competence. In addition, it examines differences between communication channels - media coverage and advertising - and between individuals. Three data sources on Switzerland are used to test these relationships: an individual rolling cross-section panel data, a media content analysis, and an advertisement content analysis. Mediation models show that the visibility of parties on issues influences perceptions of competence and thereby helps parties to attract new voters and reinforce their core voters. Furthermore, ads seem to have a stronger effect than media coverage in reinforcing people's opinions. Finally, and in line with motivated reasoning, citizens without partisan ties are more sensitive to campaign information than party identifiers.