Reverse sequential approval voting offers some fairness in limited cases
Reverse Sequential Proportional Approval Voting Rule: Proportionality and Approximation Guarantees
Computer Science and Game TheoryArtificial Intelligence
Summary
Choosing groups fairly when many people approve of different candidates can be tricky. This paper looks closely at a particular voting method called Reverse Sequential Proportional Approval Voting, which hasn’t been studied as much as similar methods. The researchers show that this method doesn’t always produce fair or optimal groups in general. However, they identify specific situations where it does give reasonable fairness and good selections.
What this means in practice
- •For electoral system designers: Design election rules for committees to ensure fair representation in settings where reverse sequential approval voting applies well.
- •For decision system developers: Implement voting-based selection systems in group decisions when fairness and optimization guarantees are needed in special cases.
A theory result. No direct application yet.
Authors
Georgios Papasotiropoulos
Abstract
We study the Reverse Sequential Proportional Approval Voting Rule (RevSeqPAV) in approval-based committee elections. Despite its historical prominence and practical use, its properties and guarantees are much less understood than those of Sequential PAV. We analyze it along two dimensions: proportional representation (measured by Extended Justified Representation, its approximations, and proportionality degree) and approximation of the maximum PAV score of instances. We first establish strong negative results for general, unrestricted election instances and then identify settings in which the rule provides meaningful fairness and optimization guarantees.