The Predictive Ability of Pre-Election Polls in Italy: A Regional Focus

The article aims to study the predictive ability of pre-election polls in Italy. Previous papers by Callegaro and Gasperoni have already studied national polls published before general parliamentary elections, using the measure of “accuracy” A originally proposed by Martin, Traugott and Kennedy (2005). This article will follow the same methods of those studies and focus on a) pre-elections polls published before regional elections and b) pre-general election polls based on regional samples. The peculiar electoral system of the Italian Senate confers a strategic importance to some regions, and for this reason some polls based on regional samples are commissioned and published. Using a data-base of published poll findings drawn from the website www.sondaggipoliticoelet¬torali.it, the article will analyze these regional polls dia-chronically and synchronically in order to highlight differences among regions. In 2010 regional elections the winning candidates’ level of support was generally underestimated by pre-election polls. In 2013 poll findings tended to severely underestimate the success of a new actor on the Italian political stage: the Five-Star Movement