When people try to mobilize voters (whether for partisan or ideological reasons, or simply to increase participation), they usually rely on at least an implicit theory about what makes people decide to vote.

On one hand, there are so many strong reasons in favor of voting that we might expect everyone to participate at every opportunity. Federal, state, and local governments collect about $2.9 trillion of our money each year and spend even more (pdf). They also make policy decisions of great importance, including the decision to wage war. By the simple and cost-free act of voting, each person gains an equal power to move this whole apparatus in the direction of his or her preferences. At the same time, voting influences who governs, thereby affecting the character, style, and principles of public leaders. Even if one ends up on the losing side of an election, a vote expresses a citizen?s values and signals his or her preferences to other citizens and political actors.

There are also strong moral arguments for voting. After all, almost all Americans see democracy as the best form of government; democracy requires widespread voting to be legitimate; and if many must vote, then no individual is morally exempt without a strong and specific excuse. By the same token, a member of an interest group or a political movement may want other members to vote so that the whole group can sway elections; but if you want others to participate, then you should vote as well. Perhaps because of these moral arguments, voting sometimes enhances or maintains reputation. People wear ?I voted? stickers with pride. Finally, groups gain political power and status if their members are known to vote, which is why they often offer arguments or inducements in favor of participation.

On the other hand, there are so many reasons against voting that we might expect no one to participate. Although there is no financial barrier, voting does take time and effort?not only to go to register, go to the polling place, and cast a ballot, but also to glean enough information that one can make a choice in line with one?s own values and preferences. Since one hundred million citizens vote in a typical modern presidential election, the marginal effect of an individual?s ballot is negligible. Even in a local election where only a few thousand ballots are cast, the cost/benefit analysis may seem to favor staying home (especially given the limited power of local officials). Furthermore, we cannot influence policy or leadership in whatever direction we might want, because the choice must always be framed before the election. There must be a limited number of candidates and/or referendum questions. It?s no solution to allow every would-be candidate and proposal on the ballot, because then the winner will take much less than a majority of the vote and almost everyone will have supported a loser.

Finally, as a form of expression, the vote can seem rather imperfect. As Walter Lippman observed in 1925: ?We go into a polling booth and mark a cross on a piece of paper for one of two, or perhaps three or four names. Have we expressed our thoughts on the public policy of the United States? Presumably we have a number of thoughts on this and that with many buts and ifs and ors. Surely the cross on a piece of paper does not express them. It would take hours to express our thoughts, and calling a vote the expression of our mind is an empty fiction.? Instead of voting, wearing a sticker or maintaining a website may seem a better form of political expression.

In practice, of course, about half of Americans vote in presidential years and about half do not. In the United States (but not in India and some other nations), participation rises with income and education. The usual explanation refers back to the cost/benefit calculation described above. Well-educated people and those with high social status can relatively easily obtain information about whom to support in an election, because they read the news for other purposes and they are on target lists for various advocacy groups. Thus the cost of participation is lower for them. The benefits may also be higher, since policy proposals and candidates tend to cater to their interests and values.

Those who try to increase turnout?of their fellow travelers or of citizens in general?have in mind these arguments for and against participation. They try to make it easier for people to make up their minds about whom to support, by providing arguments in favor of their favored candidates or relatively neutral information about the various contenders? positions and backgrounds. Since it would take a potential voter time and effort to remember Election Day and the location of his or her polling place, phone banks provide a form of free information. Groups also try to reduce the cost of voting by registering people, driving them to the polls, and advocating time-saving reforms such as online or mail-in ballots. Celebrity appeals and door-to-door visits (or phone calls) by peers are ways to impart information and may also increase the sense that voting enhances one?s reputation and status?that it is cool. Appeals to ethnic solidarity or group membership remind citizens that groups need their members to participate if they are to be treated fairly.

I need to write an article about which of these strategies work and which do not. My sense is we know something about this question, but much remains to be learned. We know that direct appeals by peers work. Face-to-face visits are best, but telephone calls are equally cost-effective. The appeals that have been tested by academic researchers are always non-partisan, because non-profit money cannot be used to test partisan messages. Therefore, we do not know whether it works better to say, ?Vote for A because he?ll cut your taxes/save your schools? or ?Vote, so that you can influence the process.? All the appeals that have been tested have worked with about the same efficiency, whether they have called on people to vote as a moral obligation, as a way to express their views, or as a form of ethnic solidarity. It is not yet clear which aspect of these appeals makes the most difference: it could be the information about how to vote, the moral plea to participate, or the idea that voting is socially desirable.

Efforts to reduce the difficulty of voting increase turnout, but not by an enormous amount (pdf). A few states send everyone a free mailing with statements by all the candidates, and one study suggests that this raises turnout by a large amount, especially among young adults who have not attended college?a group that starts with an especially low level of knowledge. It is extremely difficult to test the effect of celebrity testimonials in favor of voting, but there is no evidence that they make a difference.