An Empirical Test of the Comey Effect on the 2016 Presidential Election

Objectives The contentious 2016 U.S. presidential election was marked by acrimonious televised debates between the two major candidates, Hillary Clinton and Donald Trump, federal investigations of Clinton's emails that were sent from a personal server when she held office as Secretary of State, and the release of a videotape of lewd remarks by Trump about his behavior toward women. Financial market uncertainty also played in role in the election campaign. The objective of the article is to examine the impact of these different factors on the election. Method The present article uses a popular vote prediction market to test the impact of these factors on the probability of Trump winning the election. Results Results indicate that the debates and videotape release were not statistically significant, but that a letter to Congress released by FBI Director James B. Comey on October 28, 2016, substantially decreased Clinton's probability of winning the popular vote and simultaneously increased Trump's probability. Financial market uncertainty is found to have some marginal positive effect on Trump's probability of winning. Conclusion Trump's probability of winning the election received a substantial boost from FBI Director James B. Comey's “last‐minute” announcement on October 28, 2016.