Party-Level Characteristics and Party Switching: Evidence from Nine Western European Countries, 1990-2014

The idea that parliamentary democracy requires disciplined and cohesive political parties to function correctly is well established in the literature. Cohesive parties within legislative bodies are a crucial feature of parliamentary life, but also a necessary element to hold politicians accountable. However, an increasing body of literature has shown that parties do not always behave as unitary actors, and that discipline is often broken. One extreme form of indiscipline is party switching, which occurs when members of parliament (MPs) change their party affiliation. To date, research on party switching has either focused on the individual motivations for changing party or on the role of macro-level settings (e.g. electoral system) in shaping MPs’ incentives to engage in party switching. The role of party-level variables, instead, has received surprisingly little attention in the literature, given the potential impact that parties’ features might have on MPs' decision to change party. The aim of this Paper is to try to fill this gap by analysing whether specific features of parties are linked to party switching rates. In particular, I will test the influence of parties’ ideological position, the clarity of their label, their age and type of origin, while controlling for their size and governing status. Additionally, I will analyse the impact of intra-party democracy on the scope of switching. To test my hypotheses, I build on a self-collected database on party switching and supplement it with variables from other surveys and databases (e.g. Chapel Hill Expert Survey, Political Party Database). The final dataset includes parties from the lower chambers of nine Western European countries from 1990 to 2014. The results will improve our understanding to what extent party-level characteristics influence party switching.