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A Bayesian Hierarchical Topic Model for Political Texts: Measuring Expressed Agendas in Senate Press Releases

Published online by Cambridge University Press:  04 January 2017

Justin Grimmer*
Department of Government, Harvard University, 1737 Cambridge Street, Cambridge, MA 02138
e-mail: (corresponding author)
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Political scientists lack methods to efficiently measure the priorities political actors emphasize in statements. To address this limitation, I introduce a statistical model that attends to the structure of political rhetoric when measuring expressed priorities: statements are naturally organized by author. The expressed agenda model exploits this structure to simultaneously estimate the topics in the texts, as well as the attention political actors allocate to the estimated topics. I apply the method to a collection of over 24,000 press releases from senators from 2007, which I demonstrate is an ideal medium to measure how senators explain their work in Washington to constituents. A set of examples validates the estimated priorities and demonstrates their usefulness for testing theories of how members of Congress communicate with constituents. The statistical model and its extensions will be made available in a forthcoming free software package for the R computing language.

Research Article
Copyright © The Author 2009. Published by Oxford University Press on behalf of the Society for Political Methodology 


Author's note: I thank the Center for American Political Studies and the Institute for Quantitative Social Science for financial support. I have benefited from conversations with Ken Benoit, Matt Blackwell, Daniel Carpenter, Jacqueline Chattopadhyay, Andrew Coe, Brian Feinstein, Rob Franzese, Claudine Gay, Jeff Gill, David Hadley, Frank Howland, Emily Hickey, D. Sunshine Hillygus, Daniel Hopkins, Michael Kellerman, Gary King, Burt Monroe, Clayton Nall, Stephen Purpura, Kevin Quinn, Brandon Stewart, seminar participants at Harvard University, participants at the 2008 Summer Political Methodology meeting, and 2009 Southern Political Science Association meeting.


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