Under the influence? Understanding media’s coverage of opinion polls and their effects on citizens and politicians

Sammanfattning: News media’s use of horse race polls is a defining feature of contemporary political reporting. This thesis investigates how the news media use these opinion polls and how this coverage can influence two of the most central actors in representative democracies: citizens and politicians. This is addressed in four studies, utilizing different kinds of news content data, a representative panel survey of Swedish voters, and a large-scale survey of more than 2400 politicians. The main finding from the first study is that journalists frequently fail to adhere to statistical uncertainties when covering and explaining changes that have occurred in the polls. In more than half of the cases when journalists provide explanations for changes in the polls, the difference could be the result of sampling error. The second study examines the impact of poll coverage on subsequent political news coverage. The main finding is that there appears to be a spillover effect of how well a party is faring in public opinion and how it is portrayed in subsequent coverage. Among other things, findings suggest that parties receiving positive poll coverage are more likely to be portrayed favorably in subsequent coverage. The third study focuses on the prevalence of a bandwagon effect of poll results. Using panel data, it demonstrates how perceptions of recent developments in the polls can be an important factor in understanding how voters assess political parties and their vote intention. Voters perceiving a party to have increased its support in recent polls are more favorable towards, and more likely to say they will vote for, thus party. The fourth study focuses on how political elites view the influence of news media’s poll coverage. It finds that poll coverage is seen as an important factor that can have a considerable impact on enthusiasm among party members, the vote choice of the public, and the image of their party in the news media. Moreover, the perceived influence attributed to poll coverage is in part a function of experiences related to poll developments for the politicians’ own party. Taken together, the four studies serve as important pieces in understanding the role of news media’s poll coverage in democratic processes.