How does ranked choice voting work?

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How does ranked choice voting work?

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Ranked choice voting describes voting systems that allow voters to rank candidates in order of **preference**, and then uses those rankings to elect candidates who best represent their constituents.

RCV is straightforward for voters: rank candidates in order of choice. Voters can rank as many candidates as they want, without fear that ranking others will hurt the chances of their favorite candidate.

How the votes are counted depends on whether RCV is used to elect a single office, like a mayor or governor, or whether it is used to elect more than one position at once, like an at-large city council or a state legislature elected in a multi-winner district.

There are different ways to implement ranked choice voting, but all of them share the same core idea: voters rank candidates in order of preference.

The most common example is Instant Runoff voting, which uses the following rules:

* Tally up how many ballots each candidate appears at the top of.
* If one candidate has >50%, they win.
* Otherwise, eliminate the lowest candidate, and repeat.

Let’s take an example. Suppose that the 2020 US Presidential election had used instant runoff voting, and that there were four candidates: Bernie Sanders, Joe Biden, Generic Republican, and Donald Trump. We’ll take some example ballots:

* Voter 1: Bernie > Biden > Generic > Trump, that is, this person’s just really left-wing.
* Voter 2: Trump > Bernie > Generic > Biden, that is, this person’s anti-establishment and leans right.
* Voter 3: Bernie > Trump > Biden > Generic, that is, this person’s anti-establishment and leans left.
* Voter 4: Biden > Bernie > Generic > Trump, a pretty standard Democrat
* Voter 5: Trump > Generic > Biden > Bernie, just really right-wing
* Voter 6: Trump > Generic > Bernie > Biden, right-wing with some populist leanings
* Voter 7: Generic > Trump > Biden > Bernie, right-wing with some anti-populist leanings
* Voter 8: Biden > Generic > Bernie > Trump, generally pro-establishment and moderate
* Voter 9: Biden > Generic > Bernie > Trump, same as Voter 8.

In the first round, we tally up the first-choice votes for each candidate. In the first round, we have 2 votes for Bernie, 3 for Biden, 3 for Trump, and 1 for Generic. No one has 5 votes (>50% of the total), so we don’t have a winner yet even though Trump has the most votes. So we eliminate the worst performer, namely, Generic Republican.

That means we just delete Generic Republican from every ballot and repeat:

* Voter 1: Bernie > Biden > ~~Generic~~ > Trump, that is, this person’s just really left-wing.
* Voter 2: Trump > Bernie > ~~Generic~~ > Biden, that is, this person’s anti-establishment and leans right.
* Voter 3: Bernie > Trump > Biden > ~~Generic~~, that is, this person’s anti-establishment and leans left.
* Voter 4: Biden > Bernie > ~~Generic~~ > Trump, a pretty standard Democrat
* Voter 5: Trump > ~~Generic~~ > Biden > Bernie, just really right-wing
* Voter 6: Trump > ~~Generic~~ > Bernie > Biden, right-wing with some populist leanings
* Voter 7: **~~Generic~~ > Trump** > Biden > Bernie, right-wing with some anti-populist leanings
* Voter 8: Biden > ~~Generic~~ > Bernie > Trump, generally pro-establishment and moderate
* Voter 9: Biden > ~~Generic~~ > Bernie > Trump, same as Voter 8.

Only Voter 7’s vote changes, because they’re the one who ranked Generic first. Their vote shifts to Trump, their second choice. The count is now 2 Bernie, 3 Biden, 4 Trump. Still, no one has 5 votes, so we have to continue. The lowest-performing candidate is now Bernie, who is eliminated:

* Voter 1: **~~Bernie~~ > Biden >** ~~Generic~~ > Trump, that is, this person’s just really left-wing.
* Voter 2: Trump > ~~Bernie~~ > ~~Generic~~ > Biden, that is, this person’s anti-establishment and leans right.
* Voter 3: **~~Bernie~~ > Trump >** Biden > ~~Generic~~, that is, this person’s anti-establishment and leans left.
* Voter 4: Biden > ~~Bernie~~ > ~~Generic~~ > Trump, a pretty standard Democrat
* Voter 5: Trump > ~~Generic~~ > Biden > ~~Bernie~~, just really right-wing
* Voter 6: Trump > ~~Generic~~ > ~~Bernie~~ > Biden, right-wing with some populist leanings
* Voter 7: ~~Generic~~ > Trump > Biden > ~~Bernie~~, right-wing with some anti-populist leanings
* Voter 8: Biden > ~~Generic~~ > ~~Bernie~~ > Trump, generally pro-establishment and moderate
* Voter 9: Biden > ~~Generic~~ > ~~Bernie~~ > Trump, same as Voter 8.

This redistributes the votes or voters 1 and 3, who had Bernie ranked first on their ballots. The count is now 4 Biden, 5 Trump. Trump now has the required 50% of the vote (voters 2, 3, 5, 6, and 7) and wins.

You and your friends are trying to decide which movie to see.

Everybody calls out their first choice. If there’s no clear winner, then whichever movie got the least votes gets ruled out. But we’re looking for a movie which will make everyone at least a little bit happy, so we ask the people who voted for that movie what their second choice would be. We add their 2nd-pick votes to the existing counts for whichever movies they say, and then we check again to see if there’s a clear winner. And we keep going until there is a clear winner.

Except, of course, we ask you to make your second pick, third pick, etc at the same time as your first pick.

When you vote you rank your choices from most preferred to least preferred. If you dont like a candidate at all though, you dont have to list them. Once you do that. your done and are likely done having to think about voting unless something really unexpected happens. Everything that happens next is a part of the vote counting process.

During the vote counting process you have a threshold that someone needs to reach in order to win. Hypothetically we can say its 51% of the vote, but you can make it whatever you want, but you probably want it as a number that shows a decent majority for victory. Then you count up all the peoples preferred choices and see if someone managed to get above the threshold to win. If no one got over our threshold of 51% that we set, you drop the person with the least amount of votes. For everyone that listed the person dropped from the running as their first pick, their vote instead goes to their second preferred candidate instead. Then you simply repeat the process above until someone gets above the threshold. Dropping the lowest polling candidate and transferring their votes to the voters next preferred candidate.

Eventually someone will either win or in the unlikely situation that no one wins you do a special election where everyone has to vote again, but its just the two final candidates on the ballot with the majority winner winning.