Top regional candidate selection methods and incumbency in Spain

Party primaries were introduced as quite controversial democratic innovations in Spain during the early 2000s. Between the mid 2015s and the early 2020s, primaries were widely adopted by new and maintstream parties as a candidate (and party leader) selection methods, although its implementation has differed quite substantially between parties and periods (Astudillo and Detterbeck, 2020). This has opened the opportunity to explore the impact of different candidate selection methods as a driver of the social features of the candidates (Martínez Cantó y Astudillo, 2021). The aim of our paper is to explore the relevance of party primaries as a key factor shaping the results of top regional candidate selection processes in Spain since the mid 2010s. In particularly it will try to explore whether (and how) party primaries reinforce or weakean party incumbents (previous regional party candidates) in each selection process. For that purpose the paper relies on an origial dataset containing data of the candidate selection rules and socio-political profiles of the top regional candidates of the main Spanish parties between 1980 and 2023.