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Exploiting a Rare Communication Shift to Document the Persuasive Power of the News Media


  • We thank Steve Ansolabehere, Larry Bartels, Adam Berinsky, Andrea Campbell, Patrick Egan, Daniel Gingerich, Greg Huber, Phil Jones, Karen Jusko, Valentino Larcinese, Chap Lawson, Jens Ludwig, Tali Mendelberg, Mark Peffley, Maria Petrova, Riccardo Puglisi, Jas Sekhon, Jim Snyder, Jan Vermeer, Adam Ziegfeld, and seminar participants at Georgetown University and Yale University for helpful comments, as well as Monica Kahn, Mike Myers, and Amanda Spears for research assistance. All remaining errors are our own.

Jonathan McDonald Ladd is Assistant Professor of Government and Public Policy, Georgetown University, 3520 Prospect St. NW, 4th Floor, Washington, DC 20007 ( Gabriel S. Lenz is Assistant Professor of Political Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., E53-463, Cambridge, MA 02139 (


Using panel data and matching techniques, we exploit a rare change in communication flows—the endorsement switch to the Labour Party by several prominent British newspapers before the 1997 United Kingdom general election—to study the persuasive power of the news media. These unusual endorsement switches provide an opportunity to test for news media persuasion while avoiding methodological pitfalls that have plagued previous studies. By comparing readers of newspapers that switched endorsements to similar individuals who did not read these newspapers, we estimate that these papers persuaded a considerable share of their readers to vote for Labour. Depending on the statistical approach, the point estimates vary from about 10% to as high as 25% of readers. These findings provide rare evidence that the news media exert a powerful influence on mass political behavior.