In the lead-up to the federal elections in 2011, a Rolling Cross-Section Survey was conducted for the first time in Switzerland. Thomas De Rocchi utilizes the data collected to identify short-term changes in voter attitudes and preferences throughout the campaign and to explain these changes in relation to communication events from the campaign itself. The analyses presented thus provide important new insights regarding the influence of media reports and opinion polls on public opinion formation, as well as the underlying mechanisms at play.