Abstract The democratization of party leaders and candidates has garnered significant attention in recent decades across various countries. However, the comparative literature has devoted less attention to other internal party democratic innovations such as party internal referendums. So far, scholarly research has focused on case studies describing the rules and main features of such events, while participation remains largely unexplored. This paper aims to bridge this gap by exploring the relevance of four meso-level features on turnout: competitiveness, saliency, frequency, and length of the voting period. To test the relevance of such factors, the paper builds on an original database of 407 intra-party referendums in the Czech Pirate Party, Five Stars Movement and Podemos conducted from 2013 to 2023. The results point out the significance of more extended voting periods and proposals on public policies as the main drivers of turnout. These results also have significant consequences in the study of participation within (digital) political parties.
Barberá et al. (Thu,) studied this question.