The Dynamics of Issue Diversity in Party Rhetoric
An important property of any party system is the range of issues it presents to the electorate; what we refer to as issue diversity. This paper presents an innovative approach to measuring issue diversity and it examines what explains variation in issue diversity over time. Drawing on the dynamic representation model, this paper argues that changes in party issue diversity are shaped by changing public demands. This model is tested by analyzing party leader speeches in two parliamentary systems, Britain and Denmark, in the period 1960-2008, using vector autoregression. Our results confirm that parties’ issue agendas are driven by public preferences; yet they also highlight that parties can shape the public agenda. These findings have implications for our understanding of party competition and political representation more generally.