Join us for a collection of talks about ranked choice voting, and, of course, free pizza!
Abstract: Ranked choice voting (RCV) is an increasingly popular - although still not widely adopted - way to hold elections. The recent New York City mayoral election is one prominent example.
RCV has captured scholars’ imaginations (Lewis Carrol, Amrtiya Sen, and many others) for centuries. The most widely-used method for counting RCV ballots is known as Instant Runoff (IR). But IR has some clear shortcomings, which we will illustrate. And, interestingly, any formula that we could create to count RCV ballots will also sometimes misfire. This last fact is known most commonly as Arrow’s Theorem.
In three short presentations, we will show results about the way RCV facilitates ballot access for candidates that might otherwise be discouraged from running, we will use a “spatial model” to attempt to classify the cases where reasonable counting methods disagree, and we will see a proof of a version of Arrow’s Theorem due to Sen.