Pacific@MPSA: Why do people choose to vote by mail?
Ed. note: This is the first of several entries on our faculty’s presentations at the recent Midwestern Political Science Association annual meetings in Chicago, IL. Prof. Keith Smith and Prof. Dari Sylvester presented their results from a field experiment on the choice by voters to use vote-by-mail.
In California, voters have several options when choosing to cast a ballot during an election. A voter can go the traditional route and vote at the polling place on election day. The voter can also go to the registrar’s office and cast an early ballot. Finally, a voter can request a vote-by-mail (VBM)–i.e., absentee–ballot. In 2002, California created permanent, no-fault absentee voting, now called permanent vote by mail (PVBM), which allows voters to request and receive a mail ballot for all future elections.
As Figure 1 (below) shows, the use of PVBM by California voters has increased significantly since its creation. By Jan. 2010, one in four voters statewide was a PVBM voter and nearly one out of every two voters in San Joaquin County (where Pacific is located) was a PVBM voter.
Figure 1: PVBM Statewide and in San Joaquin County.
Why would someone choose to become a PVBM voter? Why choose to vote by mail instead of going to the polling place? The literature is largely silent on this question, though we can infer some guesses. First, someone might choose to vote by mail because it lowers their costs of voting (a la Downs 1957). If you vote by mail, you don’t have to worry about taking time off from work or finding child care to go vote; you don’t have to drive to the polling place, find parking, or wait in line; and you can take your time working through the ballot rather than feeling the pressure to vote quickly. Most people, when they think about vote by mail, think of it as a less costly and more convenient to vote.
Alternatively, people might be motivated for reasons that have little or nothing to do with personal cost. People might respond to social pressure. Gerber, Green, and Larimer (2008), for example, find a significant social pressure effect when trying to get people to vote. People might respond information about cost savings to the county from VBM. Finally, people might not be using VBM because they are concerned about voter fraud or their ballot not being counted. Perhaps they might respond to a message about the safety of VBM.
We ran a field experiment to test each of these hypotheses. We randomly assigned all registered, non-PVBM voters (~144K people after exclusions) to one of five groups. The first group, the control group, received a postcard explaining that they were not registered PVBM and informing them that if they signed and returned the card they would be. The second group got essentially the same card as the control, but its card contained a message about the convenience of voting by mail. The third group got a message about the cost savings from VBM. The fourth’s card had a social pressure message. The final group’s card had a message about the safety of PVBM.
We then waited to see who returned the cards and who did not. The results are in Table 1 below. The rates of return are substantively and statistically higher for every experimental message except convenience. People who received the social pressure message were about 10 percent more likely to return their card than people in the control group. Similarly, people who received the safety and cost savings messages were 12 percent more likely to return their cards than those in the control group.
Table 1: Experimental Effects
So what do we make of these results? First, on a practical level, if you want people to use PVBM, don’t make a convenience argument to them. In all likelihood, they know that VBM is more convenient than going to the polling place and are choosing not to VBM for some other reason. Second, on a more theoretical level, like voting the use of PVBM may not be simply about relative costs and benefits to the voter. There are likely other factors at play, factors that we do not have a good understanding of yet and need more information about.