Stable Voting

TL;DR

Stable Voting is a new ranked-ballot voting system designed to ensure consistent winners and reduce ties, based on the principle that a candidate who would win without certain opponents should still win when they are included.

Contribution

It introduces the Stable Voting system that enforces Stability for Winners and minimizes ties, a novel approach in single-winner voting methods.

Findings

Satisfies the Stability for Winners principle.

Effectively avoids tied outcomes in small elections.

Ensures consistent winners across different candidate sets.

Abstract

We propose a new single-winner voting system using ranked ballots: Stable Voting. The motivating principle of Stable Voting is that if a candidate A would win without another candidate B in the election, and A beats B in a head-to-head majority comparison, then A should still win in the election with B included (unless there is another candidate A' who has the same kind of claim to winning, in which case a tiebreaker may choose between such candidates). We call this principle Stability for Winners (with Tiebreaking). Stable Voting satisfies this principle while also having a remarkable ability to avoid tied outcomes in elections even with small numbers of voters.