Written by Edgar Wang
Edited by Etsub Yifru
With the elections coming up, the MWR has decided to post this primer on the voting system used by the MSU Congress. We use the system known as Instant Runoff Voting (IRV) that tries to ensure that everyone’s voice is heard. Understanding our voting system will enable your vote’s power to reach its full potential.
What Is It?
IRV is a voting system that is designed for elections with multiple candidates. Every voter assigns a ranking of the candidates on her or his ballot. The tallying works as follows: every round, for each candidate, they count the number of votes ranking him or her as first among the remaining candidates. Then, the candidate with the least number of votes is eliminated. The following round, those whose first choice was eliminated counts towards the votes of their second choice. This continues until only one candidate remains; the elected candidate.
For example, let’s assume that there are three candidates: Alice (A), Bob (B), and Charlie (C). There are 14 people who vote for, in this respective order, A, B & C, 15 people who vote for B, C & A, 7 people who vote for C, A & B, and 4 people who vote for C, B & A. In the first round, 14 people vote for Alice, 15 people vote for Bob, and 11 people vote for Charlie. Thus, Charlie gets eliminated. In the second round, 14 people vote for Alice in addition to the 7 people who voted C, A & B, which is equal to 21 in total. Bob, on the other hand, has 15 people vote for him in addition to the 4 people who voted C, B & A, which is equal to 19. Thus, Bob gets eliminated and Alice wins.
There are many advantages to using the IRV system. In short, it promotes large voter turnouts and issue-based voting instead of the cloggy elections involving two or three major parties. Candidates are encouraged to construct coalitions and support each other’s projects, because that increases their chances of being ranked higher alongside a preferred candidate. It gives everyone a fair shot at being elected since voters will be able to rank everyone and not feel like their vote goes to waste if their preferred candidate doesn’t win. It discourages strategically voting against certain candidates.
It turns out that tiebreaking in IRV is quite the task. The scheme MSU Congress elections adopt is the Last Round System, which consists of the tied candidate who received the least number of votes in the previous round to be eliminated.
It’s important to rank all the candidates to ensure that your vote counts. A common mistake made by people who don’t understand the IRV system is that they think the ballot is a plurality vote (e.g. the candidate in first place gets 5 points, the candidate in second place gets 4 points, etc.). Voting for only one candidate does nothing ranking all the candidates doesn’t.
For those of you who are curious about the mathematics behind this voting system, and would like to understand how and why it could go horribly wrong, you can consult the following link: http://www1.cs.columbia.edu/~unger/articles/irv.html