The Effect of Convenience Voting on Election Outcomes: Implications for Public Policy and the Study of Momentum in Campaigns

Voting-by-mail (VBM) provides voters the opportunity to cast ballots without being exposed to the information revealed in the final weeks leading up to Election Day. We assess whether the resulting informational differences between VBM and polling place voters affect electoral outcomes. We overcome the identification problem caused by the self-selection of voters into VBM by exploiting an election administration policy in California in which some precincts are assigned to be VBM-only based on an arbitrary threshold of the number of registered voters. Analyzing the 2008 California presidential primary, we show that VBM both increases the probability of selecting withdrawn candidates and affects the relative performance of candidates remaining in the race. Our findings have implications both for public policy and for the study of campaign effects and momentum in American elections. 1 On the evening of September 30, 2004, George W. Bush and John Kerry met for the first of their three presidential debates. A Newsweek poll of registered voters watching the debate found that Kerry resoundingly won; 61 % said he did a better job compared to only 17 % who selected Bush. Prior to the debate, Bush was leading Kerry 54%-43 % in the poll; after the debate, Kerry had taken a 47%-45 % lead, a substantial eleven-point swing (CNN 2004). However, Kerry’s debate victory could not help him win the votes of some individuals living in battleground states like Iowa and Ohio who cast their ballots via convenience voting prior to the debate. 1 Bush’s narrow victories in these two states helped propel him to a second term. Those individuals in Iowa and Ohio voting prior to the first 2004 presidential debate are part of a growing segment of the United States electorate using convenience voting. 2 Convenience voting is defined as any form of voting other than traditional polling place voting, of which vote-by-mail (VBM) and early in-person voting are the most common