Is It Rational to Vote? Political scientists study all aspects of voting behavior. The most interesting question, of course, is who votes for whom and why. But they have gotten bogged down on what might sound like a trivial question: why do people even bother to vote! What does Rational Choice Theory have to say on this topic?

Simple RCT Analysis of the Decision to Vote Let us assume that our prospective voter foresees a benefit B if her favorite wins. But how likely is it that her vote will make the difference that leads to victory? Call that probability P. (Her estimate of the probability that the candidate will win regardless is R.) There is also a cost C incurred by going to the polls (loss in time, the inconvenience). Let us now compute the expected utility of going to the polls.

Matrix for the Voting Decision Outcomes: Actions: Favorite Wins Favorite Loses Vote Prob = R + P Util = B - C Prob = 1 - (R + P) Util = - C Not Vote Prob = R Util = B Prob = 1 - R When we compare the two actions, we see that the expected utility of the voting option will be less than that of staying home unless P x B > C. Since any realistic estimate of P will be very small, on this analysis, no individual should ever vote!

Alternative Matrix for the Voting Decision Decisive for Victory Made No Difference to outcome Vote Prob = P Util = B - C Prob = 1 - P Util = - C Not Vote This is the status quo - no costs, no impact on the election. Actions: Outcomes: Realistically, the value of P is always going to be very small. So unless C is set at practically zero (which isn’t very realistic), the expected utility of voting will always be less than that of not voting. So from an individual perspective, no one should ever vote!

Can Decision Theory Be Modified to Explain Actual Voting Behavior? So far, RCT can not explain why people vote. But it does make some plausible sounding comparative predictions. According to RCT, overall voter turnout should increase when people’s perception of the value of B increases and that of C decreases, and when their estimate of P increases. To explain why people vote at all, however, we need to add a factor. Let’s call it D for duty. People vote when D + (P x B) > C.

Avoid Making RCT into a Toothless Tautology We could collect data to check the comparative claims of the RCT analysis of voting. (Does increased C in fact lower voter turnout?) But to say that those people who vote are the ones who think they have a duty to vote is getting pretty close to saying that the people who choose to vote are the ones who want to vote. Is there an independent way to predict who is going to feel a duty to vote? Or must we simply wait and see!

Another Reason not to Just Add In Duty RCT analyzes decisions in terms of the consequences of actions. However, the D value does not attach to outcomes but to the act itself. In parallel language we can say that most of the values that appear in the matrix are “investment” values while D is a “consumption” value. However, one could replace the duty factor with a “guilt” factor which only kicks in after friends say, “You didn’t vote?”

Other Attempts to Explain the Decision to Vote Prospect Theory tells us that people often overestimate the numerical value of small probabilities. Could people have inflated ideas about how likely it is that their individual vote would be decisive? Regret Theory (see Plous, pp ) suggests another possible explanation.

Regret Matrix for the Voting Decision Outcomes: Actions: So Close That My Vote Was Decisive Not that Close Vote My candidate won so no regrets! My vote didn’t matter so regret of C Not Vote Because I didn’t vote, my candidate lost. Regret of B My vote wouldn’t have mattered anyway - no regrets The rule of Minimizing Maximum Regret predicts people should choose to vote since B will typically be much larger than C.

Other Psychological and Sociological Accounts Other approaches talk about how interested people are in politics, the extent to which they are identified with a party that mobilizes voter turnout, the degree to which they feel alienated from society, the attitudes of their friends, etc. Many of these considerations can be incorporated into RCT, either as additional costs or as duty-like considerations. None of them speak to the core issue of whether an individual thinks their single vote could make a difference.

Brief summary of Empirical Studies For about half of the population the factors that appear in RCT have no effect on their behavior - they are moved simply by Duty. For the other half, considerations of B, P and C are influential but these factors are not combined in the manner dictated by RCT. These people are more apt to vote in close elections, but they seem to be thinking that if they vote maybe lots of other folks like them will also turnout and together they will make a difference. Blais believes people may simply add B and P instead of taking their product. C has the least effect.