Do Shark Attacks Influence Presidential Elections? Reassessing a Prominent Finding on Voter Competence


We reassess Achen and Bartels’ (2002, 2016) prominent claim that shark attacks influence presidential elections. First, we assemble data on every fatal shark attack in U.S. history and countylevel returns from every presidential election between 1872 and 2012, and we find no systematic evidence that shark attacks affect elections. Second, we show that Achen and Bartels’ county-level finding for New Jersey in 1916 becomes substantively smaller and statistically weaker under alternative specifications. Third, we find that their town-level finding in Ocean County significantly shrinks when we correct errors and does not hold for the other beach counties. Lastly, implementing placebo tests in state-elections where there were no shark attacks, we demonstrate that Achen and Bartels’ result was likely to arise even if shark attacks do not influence elections. Overall, there is little compelling evidence that shark attacks influence presidential elections, and any such effect—if one exists—is substantively negligible.

Journal of Politics
Andrew B. Hall
Andrew B. Hall
Professor of Political Science

Professor of Political Science at Stanford University