Party System Dynamics: New Tools for the Study of Party System Change and Party Transformation

New patterns of party system change are affecting political systems in ways that we are only now beginning to understand, but the speed of change actually inhibits our understanding because it also disrupts the very measures we use to look at party system change. This increasing state of constant flux is also stretching our concepts and is more difficult to measure: how we interpret the merging, the splitting, the regionalisation or de-nationalisation of main parties, when we consider a party to be new, how we compute volatility when voters can choose among multiple parties’ candidates or when voters can choose among party lists, and so on. Therefore, we need more comprehensive concepts and new techniques to better measure and understand the nature of changes within party systems. Drawing on a detailed and extensive data set, the paper focuses on three aspects: the identification of the components of party system dynamics, the development of better measurements of party system change; and an application of the new methods to actual political systems.

(This is a joint-authored paper written by Kevin Deegan-Krause, Mariano Torcal, Fernando Casal Bertoa and Tim Haughton)