Francesco D’Acunto & Gaia Narciso
For the third time in six years, Italians are called to vote for their national representatives. It is the sixth time that electors vote in a context of media bias. For ten years during the period 1994-2011, Berlusconi has controlled six out of seven national channels, due to his dual role as a media tycoon and prime minister. Besides the anecdotal evidence, Durante and Knight (2012) recently investigated the extent of the media bias towards Berlusconi, and have estimated its magnitude in terms of time and quality of coverage of Berlusconi’s party and opponents.
But how much does media bias affect electoral outcomes? Della Vigna and Kaplan (2007) provide evidence that the introduction of Fox News increased Republican vote by 0.4 to 0.7 percentage points in the 2000 Presidential elections. Enikolopov et al (2011) analyse the 1999 Parliamentary elections in Russia and document that availability of an independent national TV channel decreased the vote for the government party by about nine percentage points.
Our recent work addresses the Italian case (Barone et al 2012). This case is interesting because, contrary to the US and Russia, all Italian voters know that Berlusconi owns the major commercial TV network since the early eighties. We exploit exogenous variation in viewers’ exposure to Berlusconi bias using idiosyncratic deadlines to switch to digital TV from 2008 to 2012. At the deadlines, old analogue signals were switched off and only digital signals kept on airing. Digital TV improved transmission efficiency, and increased the number of free national channels tenfold. Most digital channels are aired by new media companies, which have no ties to Berlusconi. After switching to digital TV, many Italian households changed their viewing habits. From June 2008 to June 2011, the share of viewers of Berlusconi-controlled channels dropped from 84% to 71%. Over the same period, viewers of new channels increased from 2% to 17%. We explore the causal effect of the shock to bias exposure on voting behaviour at regional elections in March 2010, the first elections held during the switch-off process. We look at Piedmont, a region where western towns switched to digital TV in autumn 2009, while eastern towns switched in autumn 2010. This setup allows us to compare the electoral outcome of Berlusconi’s party between municipalities that were exposed to the new digital channels and those where the digital switch-off had not taken place yet. In order to