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The Minimal Persuasive Effects of Campaign Contact in General Elections: Evidence from 49 Field Experiments



Significant theories of democratic accountability hinge on how political campaigns affect Americans’ candidate choices. We argue that the best estimate of the effects of campaign contact and advertising on Americans’ candidates choices in general elections is zero. First, a systematic meta-analysis of 40 field experiments estimates an average effect of zero in general elections. Second, we present nine original field experiments that increase the statistical evidence in the literature about the persuasive effects of personal contact tenfold. These experiments’ average effect is also zero. In both existing and our original experiments, persuasive effects only appear to emerge in two rare circumstances. First, when candidates take unusually unpopular positions and campaigns invest unusually heavily in identifying persuadable voters. Second, when campaigns contact voters long before election day and measure effects immediately—although this early persuasion decays. These findings contribute to ongoing debates about how political elites influence citizens’ judgments.


Corresponding author

Joshua L. Kalla is a Graduate Student, Department of Political Science, University of California, Berkeley.,
David E. Broockman is an Assistant Professor, Stanford Graduate School of Business.,


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We acknowledge seminar participants at the Midwest Political Science Association conference, the Northeast Political Methodology Meeting at NYU, Berkeley, Stanford, and the University of British Columbia, as well as Adam Berinsky, Donald Green, Avi Feller, Shanto Iyengar, Jon Krosnick, Gabriel Lenz, Joel Middleton, Daron Shaw, Jas Sekhon, Eric Schickler, Laura Stoker, and Lynn Vavreck for helpful feedback. All remaining errors are our own. The original studies reported herein were conducted by Working America. The authors served as unpaid consultants to Working America in their personal capacity.



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