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Birds of the Same Feather Tweet Together: Bayesian Ideal Point Estimation Using Twitter Data

Published online by Cambridge University Press:  04 January 2017

Pablo Barberá*
Wilf Family Department of Politics, New York University, 19 W 4th Street, 2nd Floor, New York, NY 10012., e-mail:
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Politicians and citizens increasingly engage in political conversations on social media outlets such as Twitter. In this article, I show that the structure of the social networks in which they are embedded can be a source of information about their ideological positions. Under the assumption that social networks are homophilic, I develop a Bayesian Spatial Following model that considers ideology as a latent variable, whose value can be inferred by examining which politics actors each user is following. This method allows us to estimate ideology for more actors than any existing alternative, at any point in time and across many polities. I apply this method to estimate ideal points for a large sample of both elite and mass public Twitter users in the United States and five European countries. The estimated positions of legislators and political parties replicate conventional measures of ideology. The method is also able to successfully classify individuals who state their political preferences publicly and a sample of users matched with their party registration records. To illustrate the potential contribution of these estimates, I examine the extent to which online behavior during the 2012 US presidential election campaign is clustered along ideological lines.

Research Article
Copyright © The Author 2014. Published by Oxford University Press on behalf of the Society for Political Methodology 


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