Introduction

Instant Runoff Voting (IRV), also known as the Single Transferable Vote or Ranked Choice Voting, is an electoral system that allows voters to rank candidates in order of preference. When votes are counted, the candidate with the fewest votes is eliminated, and their votes are redistributed to the remaining candidates based on voters’ preferences. This process repeats until one candidate receives more than 50% of the votes, emerging as the winner.

This article will provide a step-by-step guide on how to calculate IRV, ensuring that even newcomers to this voting method can understand and apply it effectively.

Step 1: Understand the Ballot

To effectively calculate IRV, understanding the ballot structure is crucial. Each voter receives a ballot listing all candidates. The voter ranks these candidates in order of preference, with “1” being their first choice, “2” their second, and so on.

Step 2: Initial Count

Once all ballots are submitted, perform an initial count of first-choice preferences. This involves counting how many “1” rankings each candidate received.

Step 3: Determine If There’s a Majority Winner

Calculate if any candidate has received over 50% of the first-choice votes. If a majority winner exists in this initial count, they are declared as the winner. If not, proceed to step 4.

Step 4: Eliminate the Last Place Candidate

Identify the candidate with the lowest number of first-choice votes. This candidate is now eliminated from the race.

Step 5: Redistribute Votes from Eliminated Candidates

For each ballot where the eliminated candidate was marked as the first choice, transfer its vote to their next preferred candidate (i.e., whoever was ranked second). If there’s a tie among last-place candidates, eliminate them all simultaneously and redistribute their votes accordingly.

Step 6: Repeat Steps 3-5 Until a Majority Winner is Found

Repeat the process of checking for a majority winner, eliminating last-place candidates, and redistributing votes until one candidate has over 50% of the votes. This candidate is declared the winner.

Step 7: Declare the winner

Once a candidate secures more than 50% of the votes, announce them as the winner of the election.

Conclusion

Instant Runoff Voting ensures that the winning candidate has wide support among voters and eliminates the possibility of “wasted” votes — this is because even if a voter’s top choice is eliminated early, their lower preferences still play a part in deciding the outcome. By following this step-by-step guide, you can accurately calculate IRV and gain a better understanding of this increasingly popular voting system.