Plurality voting (FPTP)

Also called first past the post (FPTP), choose-one voting or winner take all.

Plurality voting is the simplest way to vote: everyone picks one option, and whichever gets the most votes wins, even if that's less than half. It isn't ranked voting at all, but it's the method every ranked method is trying to improve on.

Nickname: The popularity contest
Origin: As old as voting itself
Used for: Most U.S. elections, the U.K. House of Commons, and the national parliaments of Canada and India
Best at: Being quick and simple to vote and to count
Watch out for: Similar options splitting their fans

How it works

Everyone picks one. Each voter marks a single option.
Count the votes. Add up how many voters picked each option.
Most votes wins. No majority is needed, just more votes than anyone else.

The name comes from horse racing: the first horse past the post wins, however close the race and however many horses ran.

Example: nine friends pick dinner. Four love tacos, three love sushi and two love pizza. But five of the nine would rank tacos dead last, and all nine would be happy with pizza.

	🌮 Tacos	🍣 Sushi	🍕 Pizza
Votes	4, wins	3	2

Tacos wins with four of nine votes, so more than half the group eats the dinner they wanted least. A single vote can't tell “second favorite” from “absolutely not.” See this vote in the story.

A short history

Ancient
Votes by show of hands are as old as voting. The assembly of ancient Athens decided most questions that way.
1341
England's House of Commons takes shape. For centuries, most of its districts elect two members at once by plurality. Not until a 1948 law does every district elect just one.
1912
In the U.S. presidential election, former president Theodore Roosevelt runs as a third-party candidate against his own party's nominee, William Howard Taft. They split Republican voters, about 27% and 23%, and Woodrow Wilson wins with about 42%.
1950s
The French political scientist Maurice Duverger describes a pattern now called Duverger's law: plurality voting tends to leave two big parties, because voting for a third feels like wasting your vote.
2005
In the U.K. general election, 52% of all votes go to candidates who lose their district.
2011
U.K. voters keep FPTP, rejecting a switch to instant runoff voting (IRV), called the alternative vote there, by about two to one.

Strengths and weaknesses

Strengths

The simplest possible ballot. One mark. It's quick to vote, hard to get wrong, and easy to explain to anyone.
Fast, easy counting. Every polling place counts its own votes, and the totals simply add up. Results can be known the same night.
Clear winners. Ties are rare, and there's no complicated tiebreaker to explain.
Your favorite is never hurt by a backup. There's only one choice on the ballot, so nothing later on it can work against your favorite.

Weaknesses

The spoiler effect. Two similar options split the voters who like them, and an option fewer people like can win. That's what happened in 1912.
Winners without a majority. With three or more options, the winner can have far less than half the votes, and can even be the option most voters like least.
Pressure to vote strategically. Voters are pushed to pick whichever option seems likely to win instead of their real favorite, to avoid “wasting” their vote.
Lots of votes don't matter. Every vote for a losing option, and every vote a winner didn't need, has no effect on the result.
Second choices are thrown away. An option nearly everyone likes can lose to one that a passionate few love and everyone else dislikes.

How it does on the fairness tests

Passes: if more than half the voters pick an option, it wins.
Passes: your favorite can't be hurt by a backup, since there's no backup on the ballot.
Passes: more votes never make an option lose.
Passes: votes can be counted in separate places and added up.
Fails: an option that would beat every other one-on-one can still lose.
Fails: similar options split the vote.

Compare every method's results

Questions

Is plurality voting a kind of ranked voting?: No. Voters pick only one option, so there are no rankings to count. It's included here because it's what most ranked methods are designed to improve on.
What is a spoiler?: An option that can't win but pulls enough votes from a similar option to change who does win.
Is plurality the same as majority?: No. A majority means more than half the votes. A plurality just means more votes than anyone else, which can be much less than half.
Why is it called first past the post?: Like a horse race, the winner only has to finish ahead of everyone else. There's no line, such as 50%, it has to cross.