Political Advertising in Consolidating Democracies: Locally Dominant Parties and the Equalization of Media Access in Mexico
67 Pages Posted: 21 Aug 2014 Last revised: 24 Aug 2014
Date Written: 2014
To combat disparities in access to political advertising -- an essential challenge for many consolidating democracies where political parties are regionally dominant -- many countries now regulate access to political advertising. Unlike consolidated democracies, where voters are similarly familiar with the policies of the major parties, equalizing political advertising opportunities may particularly benefit political parties that are not locally dominant. Mexico implemented such a reform in 2007, allocating radio and television advertising slots according to national and state vote shares at the previous election. Using detailed signal coverage data, we combine matching techniques with a fuzzy geographic regression discontinuity design to exploit differences in exposure to political advertising caused by cross-state spillovers to identify the effects of political advertising. We show that political advertising -- particularly AM radio -- is effective at increasing the vote share of the PAN and PRD, but not the previously-hegemonic PRI. Consistent with our formal model, PAN and PRD political advertising is most effective in the least informed and politically uncompetitive electoral precincts, and when a facing a locally dominant party of intermediate strength.
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