Just Published! Competing Principals 2.0? Facebook, Renzi and the 2013 Head of State Election


Competing Principals 2.0? The impact of Facebook in the 2013 selection of the Italian Head of State

Italian Political Science Review / Rivista Italiana di Scienza Politica

Acknowledgments: Alberto Fragapane and Alessandra Cremonesi for their contribution to data collection. Two anonymous leaders of the former right-wing PD minority faction for providing ‘expert’ information on the factional affiliation of PD MPs.

Replication material: 

andreaceron.com/publications OR http://thedata.harvard.edu/dvn/dv/ipsr-risp

What is worth remembering:

  • Facebook pressure did not affect MPs’ propensity to express public dissent over the party line
  • Contrary to the general wisdom, unexperienced MPs selected through primaries did not conform to social media requests
  • Social media were not (yet) a new ‘competing principals’
  • More traditional ‘principals’ played a role: factional membership, seniority, primary
  • ‘Sentimeter’ guys were right
  • It’s not so easy to publish ‘negative’ findings!


Motivated by the literature on ‘competing principals’, this article studies the effect of interactive social networking sites on the behavior of politicians. For this purpose, 12,455 comments posted on the Facebook walls of 423 Italian MPs have been analyzed to assess whether Facebook played a role in the selection of the Italian Head of State in 2013, enhancing responsiveness. The statistical analysis reveals that the pressure exerted through social media did not affect MPs’ propensity to express public dissent over the party line, which is instead affected by more traditional ‘principals’ and factors: seniority, primary elections, and factional membership.

Just Printed! Brave rebels stay home: Whipping factionalism in parliamentary votes


Brave rebels stay home. Assessing the effect of intra-party ideological heterogeneity and party whip on roll-call votes

Party Politics (Journal IF: 1.488)

First published: January 24, 2013

Replication material: andreaceron.com/publications

Acknowledgments: Luigi Curini and Francesco Zucchini for sharing data; Luigi Curini and Marco Mainenti for comments

What is worth remembering:

  • Link between intra-party ideological heterogeneity and party unity in roll call votes (RCVs)
  • Measure policy position of intra-party factions through quantitative text analysis of congress motions
  • Provide index of intra-party polarization external to parliamentary debates
  • Heterogeneity of policy preferences lowers party unity in RCVs
  • This effect is conditional on the strength of whipping tools available to the party leader (e.g. centralized or decentralizes candidate selection; open list PR versus other electoral systems)
  • Rebels can stay home: strategic absences are a fourth voting option beyond ‘Yes’, ‘No’ and ‘Abstain’ that must be taken into account when analyzing RCVs


Sanctions and homogeneity of intra-party preferences are the two main pathways to party unity in roll-call votes. However, only a few works have managed to properly measure the degree of polarization within the party, and therefore the link between ideological preferences and parliamentary voting behaviour has not yet been fully tested. Looking at the internal debates held during party congresses and analysing motions presented by party factions through quantitative text analysis, the present article provides a new measure of intra-party polarization that is exogenous to the parliamentary arena. This measure is used to disentangle the effect of ideological heterogeneity on MPs voting behaviour, net of the party whip. Our results show that factional heterogeneity negatively affects party unity. This effect, however, is conditional on the strength of whipping resources available to the party leader. When the electoral system or the intra-party candidate selection process allows strong discipline to be enforced, the negative effect of heterogeneous preferences on party unity is lower or no longer significant. However, since absences can be a strategy by which to express dissent while avoiding sanctions, they should be considered as an additional voting option and this is crucial to understanding the impact of intra-party heterogeneity on party unity.