A Better Voting Method: Ranked-Choice Voting

Ranked-choice voting (also known as instant-runoff voting) is a common alternative to plurality first-past-the-post voting, where the candidate who gets the most votes win, regardless of win percentage. This system of election is used to elect the members of Congress in Maine, to elect the Australian House of Representatives, the Presidents of Ireland and India, and in many local elections (New York City will start using this voting method for local offices starting 2021). The Academy Awards are also chosen with this form of voting.

This method of voting ensures that a party gets a majority (greater than 50%), and eliminates the spoiler effect, a phenomenon that occurs from plurality voting, meaning that with ranked-choice voting, it will be feasible to have more than two parties (there won’t be the danger of a third party appearing, taking votes away from a major party, causing it to lose). To understand how it works, let’s simulate an election here.

There are five parties running: the Red, Blue, Green, Yellow, and Orange Parties. When voting, rather than select one candidate out of the five, voters rank each candidate in order of their preference. (For simplicity’s sake, let’s also say that Red and Blue are the largest parties — neither of the parties is too extreme). A voter’s ballot may look like this:

Whereas under the plurality system the voter might be forced to pick the Blue Party or the Red Party rather than the Green Party (for fear that the Green Party may lose as they are not one of the two major parties), now, they can rank all their candidates in the order of their preference. To determine the winner of the election, let’s take a look at the following graph of voters’ first choices:

Because Orange has the fewest votes, he is eliminated from the race. Orange’s voters all put Yellow as their second choice, so all of Orange’s votes go to Yellow instead. This is the first “runoff.”

In the second runoff, since Green has the next fewest candidates, it is eliminated from the race. Because Green’s voters selected Red as their next choice, all of Green’s votes go to Red instead (note the change in value on the axes):

Because none of the three remaining candidates are at a majority yet (a majority is defined as more than half of the voters), one more runoff is held. In this runoff, as Blue has the fewest votes, it is eliminated. Blue’s voters picked Yellow as their second choice, so Blue’s votes all go to Yellow:

Finally, we now have a majority, with Yellow having 55% of the vote. Because Yellow has a majority, it has won the election. In essence, the way that runoff voting works is as follows:

• Count voters’ first choices.  
  • If a candidate has a majority:                      
    • The winner is found.
  • Else:           
    • Eliminate the last-place candidate                      
    • Redistribute the eliminated candidate’s ballots.  
• Repeat until the winner is found.  

Because voters don’t need to worry about their votes going to waste by voting for a minor candidate, voters are more likely to vote for the candidate that they actually like, thereby incentivizing more people to participate in the political process.   That is not to say that the ranked-choice method has no disadvantages. For example, it is still susceptible to gerrymandering, is not a proportional voting method, and it still ultimately trends toward having two parties. However, all of these disadvantages are shared by the plurality system, too. The greatest advantage ranked-choice gives is eliminating the spoiler effect.  

Why haven’t voting methods been changed yet? That is because the plurality voting system favors the two biggest parties. And because the two biggest parties are often in control of governments, there is no incentive for them to deviate from the status quo.