title: Scaling and universality in proportional elections.
abstract: A most debated topic of the last years is whether simple statistical physics models can explain collective features of social dynamics. A necessary step in this line of endeavor is to find regularities in data referring to large-scale social phenomena, such as scaling and universality. We show that, in proportional elections, the distribution of the number of votes received by candidates is a universal scaling function, identical in different countries and years. This finding reveals the existence in the voting process of a general microscopic dynamics that does not depend on the historical, political, and/or economical context where voters operate. A simple dynamical model for the behavior of voters, similar to a branching process, reproduces the universal distribution.
authors.affiliation: Complex Networks Lagrange Laboratory (CNLL), ISI Foundation, Torino, Italy.
authors.forename: Santo
authors.initials: S
authors.lastname: Fortunato
authors.forename: Claudio
authors.initials: C
authors.lastname: Castellano