Jonathan N. Wand - Kenneth W. Shotts - Jasjeet S. Sekhon - Walter R. Mebane, Jr. - Michael C. Herron - Henry E. Brady
To assess the claim that the butterfly ballot used in Palm Beach County, Florida, affected the outcome of the 2000 presidential election, we provide a statistical analysis of the vote share received by Reform Party Presidential candidate Patrick Buchanan. Our analysis demonstrates that Buchanan's vote share in the county was much greater than would be expected given plausible models of the popular vote. In particular, using robust estimation of an overdispersed binomial regression model, we show that in a collection of 3,015 counties from across the United States, Palm Beach County had the second most anomalous Buchanan vote share. Palm Beach County also had the most anomalous Buchanan vote share in Florida. We also find that Buchanan's vote share among Palm Beach County's election day voters, who used the butterfly ballot, was four times as large as his vote share among the county's absentee voters, who did not use the butterfly ballot. Finally, we analyze precinct-level data from Palm Beach County and find patterns that are consistent with the hypothesis that the butterfly ballot caused Democrats to vote mistakenly for Buchanan.