Tracing the electorate of the MoVimento Cinque Stelle: an ecological inference analysis

The 2013 Italian parliamentary election was characterized by the outstanding performance of the MoVimento Cinque Stelle, which in its first participation in a general election obtained a remarkable 25% of the national vote. Where did these votes come from? Furthermore, is it possible to observe different electoral dynamics across geographical areas of Italy? In order to address these questions, we first estimate the flow of votes between the 2008 and 2013 general elections by applying an ecological inference method-the Goodman model to the entire Italian voting population, and then we take a closer look at the differences in the four geopolitical areas in which Italy is traditionally divided. We find that the extraordinary performance of the MoVimento 5 Stelle was largely due to its capacity of attracting similar amounts of former Partito Democratico and Popolo della Liberta supporters, as well as a considerable amount of voters from their traditional allies: Lega Nord and Italia dei Valori. The MoVimento 5 Stelle was also able to mobilize previous non-voters. We shed light on the territorial features of these dynamics.