Where do vox votes come from? A study case on the votes' origin of the extreme right in Madrid's region

Usually, the origin of the votes is estimated from surveys through the so-called transfer matrices. Through ecological inference, this paper analyses the vote’s provenance of a relatively young Spanish far-right political force (Vox) is analyzed. In each census section, ecological inference techniques are used to estimate the electoral transfer matrices in a context of high volatility in voters, such as the one experienced by Spain after the economic and institutional crisis that erupted with the 2009 Crash (Roig, 2009; Simon, 2019). It is intended to know the disaggregated behaviour of the electorate that Vox attracts from aggregate data. For this, a new ecological inference algorithm, rslphom, is used, specially designed to maximize the precision of the estimates at the local level. This algorithm represents an improvement within a new family of Iphom ecological inference models recently developed (Pavía and Romero, 2022), which have shown great precision (Pavía and Romero, 2023). This research is limited to Madrid’s Region. Specifically, the paper focuses on the origin of Vox’s electoral support and its evolution in the two general elections of 2019 (April and November), the regional elections of May of that same year, and the regional elections of May 2021. Vox is a relatively young party in Spain, which participated in general elections in 2015 for the first time, although it did not obtain representation in the Congress of Deputies until 2019. The transfer matrix will allow knowing the votes’ origin, and their determination. This work aims to identify the profile of the voter who opts for Vox based on their political origin (if they come from the PP or the PSOE, for example), and their relationship with their context. Transfer matrices will be studied based on the percentage of foreigners in the census section or the average wealth of residents, going beyond the traditional memory and voting intention. The working hypothesis is that there are people with high and low income among Vox voters, that is, people from different social classes (lower social class, middle social class, and upper social class). The vehicular question of the investigation is whether Vox is a catch-all party, one of a transversal nature that has voters throughout the whole society, according to Kirchheimer (1996).