Voting is not rational (usually.)

araneae

Today is the midterm elections in the United States, and I am not voting.

For the vast majority of elections, voting is irrational, because the individual's vote is proportionately very small. This means it cannot have an effect on the outcome.

There are, however, conditions which can lead to voting becoming rational, and these are:

The number of voters approaches zero.
The ratio of votes for candidates (in a majority wins, 2 person race) approaches .5
The difficulty of voting becomes vanishingly small.
Incentives are created to make the costs of not voting greater than the cost of voting (for instance, not voting is illegal in Australia, and incurs a fine.)

For me, as for nearly everyone, voting this year is irrational. 1 and 2 are nowhere close to true, and 3 is especially bad for me this year. I forgot to change my address on my voter's registration until yesterday and my polling location is both a) usually overpopulated and filled with long lines and b) farther than I care to go.

Only 3 and 4 are something that we can certainly do something about. The web-based absentee voter system that was tested this fall is a step in that directions, but its subsequent hacking was unsurprising. Is opening our system up to fraud a reasonable trade-off to get more people to vote? Should there be an option to use paper absentee-like ballots even if you are not absent? Should the U.S. go the Australia route?

Today is the midterm elections in the United States, and I am not voting.

For the vast majority of elections, voting is irrational, because the individual's vote is proportionately very small. This means it cannot have an effect on the outcome.

There are, however, conditions which can lead to voting becoming rational, and these are:

The number of voters approaches zero.
The ratio of votes for candidates (in a majority wins, 2 person race) approaches .5
The difficulty of voting becomes vanishingly small.
Incentives are created to make the costs of not voting greater than the cost of voting (for instance, not voting is illegal in Australia, and incurs a fine.)

The more irrational it is to vote, the stronger the selection bias in the voting population in favour of irrational voters. You might prefer (as I do) that politicians be elected by as rational a population as possible, all else being equal.

(On the other hand, the same bias that reduces voting by more rational people probably also reduces voting by more selfish people, since such benefits as there are from voting typically accrue to the population at large. I'm not sure what level of selfishness I want among the voting population.)

If it means my bayesian altruists are doing something more effective than queuing at the polling station, I'm happy with that.