That is, not for that reason. My guess is that most people vote because they think that by voting they will make some difference to the outcome of the election. This is almost always false.

One person’s vote in a federal election will almost never change the outcome of who is elected for their seat (in Parliament in the U.K., or in Congress or in the Electoral College in U.S. federal elections). It doesn’t really matter how close the race is projected to be – the chances of one vote making the difference in your constituency are very small regardless. In order for one person’s vote to make a difference, the person who won would have to have won by 1 or 2 votes – this almost never happens.

So is Proportional Representation the answer to this particular problem? No. Proportional Representation is similar, because one person’s vote almost never makes a difference in terms of whether a party gets an extra seat or not at the federal level with some sort of proportional scheme. If you have 500 seats, say, and a purely proportional system, with 50,000,000 people voting (these numbers are similar to the German Bundestag, which uses a modified form of Proportional Representation), then to get a seat requires 100,000 votes. What are the chances your one vote would push your party over that line and into another seat? About 1 in 100,000, or a chance of 0.001%. I.e., statistically speaking it will not happen.

(For comparison, your chances of being killed by an asteroid impact are about 1 in 700,000. Campaigns urging people to vote by saying things like “Make your vote count!”, with the inference that one person’s vote will make a difference, would be like campaigns urging people to put large shields in place over their houses by saying things like “Make your home safe from asteroids!”)

Here are some reasons that might be good ones to vote: patriotic duty, want to tell friends who you voted for, want to encourage other people to vote (although this in turn might not be rational if you think you will therefore change the result of the election, unless lots of people’s votes depend on you voting, which is unlikely), possible fine if you don’t go to the polling booth (Australia), congruence of actions with political beliefs and ideals, … No need to delude ourselves about the power of one vote. One vote counts, but unfortunately only once, which almost never makes the difference in elections as large as federal ones.