Jumping on the Bandwagon? Explaining fluctuations in party membership levels in Europe

This paper explores how party-specific contextual factors explain variations in membership levels. Based on a subset of MAPP data that includes 2898 yearly points for 262 parties 24 countries over period from 1990 to 2014, it examines three sets explanations: the lifecycle model (party age), bandwagon (electoral performances and governemental participation), competition (effective number parties). Our results confirm ratios present an overall decreasing trend across time. At same time, we show this is flattening there are important parties. Fluctuations part party’s lifecycle. also point toward effect whereby party levels increase or decrease according electoral performances, patronage boost linked governmental participation. Finally, system fragmentation decreases individual parties’ ratios. Overall, our findings complement story decline calls further investigations explanations.