# Justified representation in approval-based committee voting

@article{Aziz2014JustifiedRI, title={Justified representation in approval-based committee voting}, author={Haris Aziz and Markus Brill and Toby Walsh}, journal={Social Choice and Welfare}, year={2014}, volume={48}, pages={461-485} }

We consider approval-based committee voting, i.e. the setting where each voter approves a subset of candidates, and these votes are then used to select a fixed-size set of winners (committee). We propose a natural axiom for this setting, which we call justified representation ($$\mathrm {JR}$$JR). This axiom requires that if a large enough group of voters exhibits agreement by supporting the same candidate, then at least one voter in this group has an approved candidate in the winning committee…

## Tables and Topics from this paper

## 204 Citations

Approval-Based Committee Voting under Incomplete Information

- Computer Science
- 2021

The complexity of some fundamental computational problems for a number of classic approval-based committee voting rules including Proportional Approval Voting and Chamberlin–Courant are studied.

Strategic Voting under Incomplete Information in Approval-Based Committee Elections

- 2021

In approval-based committee elections, voters vote by submitting an approval ballot, which indicates which candidates the voter approves of, with the purpose of electing a fixed size committee.…

The Price of Justified Representation

- Computer ScienceArXiv
- 2021

This work derives worst-case bounds on the loss of welfare/coverage that is caused by imposing JR, study the computational complexity of finding ‘good’ committees that provide JR, and examine this setting empirically on several synthetic datasets.

Market-Based Explanations of Collective Decisions

- Computer ScienceAAAI
- 2021

This work considers approval-based committee elections, in which a size-k subset of available candidates must be selected given approval sets for each voter, and proposes two new solution concepts,stable priceability and balanced stable priceability, and shows that they select arguably fair committees.

The excess method: a multiwinner approval voting procedure to allocate wasted votes

- Business
- 2021

In using approval voting to elect multiple winners to a committee or council, it is desirable that excess votes—approvals beyond those that a candidate, especially a shoo-in, needs to win a seat—not…

Some Notes on Justified Representation∗

- 2016

Multi-winner voting systems are often applied to scenarios in which it is desirable that the set of winners represents the different opinions or preferences of the agents involved in the election.…

Group Fairness in Committee Selection

- Computer ScienceACM Trans. Economics and Comput.
- 2020

The main result is to show that stable lotteries always exist for these canonical preference models, given preferences of voters over committees, and the procedure for computing an approximately stable lottery is the same for both models.

Group Fairness in Committee Selection

- Computer ScienceEC
- 2019

The main result is to show that stable lotteries always exist for these canonical voter preference models, and the procedure for computing an approximately stable lottery is the same for both models and therefore extends to the setting where some voters have the former preference structure and others have the latter.

Committee Voting with Incomplete Approvals

- Computer ScienceArXiv
- 2021

We investigate approval-based committee voting with incomplete information about voters’ approval preferences. We consider several models of incompleteness where each voter partitions the set of…

The Excess Method: A Multiwinner Approval Voting Procedure to Allocate Wasted Votes

- 2018

In using approval voting to elect multiple winners to a committee or council, it is desirable that excess votes — approvals beyond those that a candidate needs to win a seat — not be wasted. The…

## References

SHOWING 1-10 OF 75 REFERENCES

Voting for Committees in Agreeable Societies

- Mathematics
- 2014

We examine the following voting situation. A committee of $k$ people is to be formed from a pool of n candidates. The voters selecting the committee will submit a list of $j$ candidates that they…

Satisfaction Approval Voting

- Political Science
- 2010

We propose a new voting system, satisfaction approval voting (SAV), for multiwinner elections, in which voters can approve of as many candidates or as many parties as they like. However, the winners…

Some Notes on Justified Representation∗

- 2016

Multi-winner voting systems are often applied to scenarios in which it is desirable that the set of winners represents the different opinions or preferences of the agents involved in the election.…

A minimax procedure for electing committees

- 2007

Abstract
A new voting procedure for electing committees, called the minimax procedure, is described. Based on approval balloting, it chooses the committee that minimizes the maximum Hamming distance…

Approximation Algorithms and Mechanism Design for Minimax Approval Voting

- Computer ScienceAAAI
- 2010

A polynomial-time 2-approximation algorithm that uses a natural linear programming relaxation for the underlying optimization problem and deterministically rounds the fractional solution in order to compute the outcome improves upon the previously best known algorithm that has an approximation ratio of 3.

Sincerity and manipulation under approval voting

- Political Science
- 2013

Under approval voting, each voter can nominate as many candidates as she wishes and the election winners are those candidates that are nominated most often. A voter is said to have voted sincerely if…

Computer-assisted constrained approval voting

- Computer Science
- 1993

The problem of constrained approval voting is formulated as an integer programming problem and a numerical example illustrating a possibility to apply the discussed voting procedure in the election of members of the Committee for Organization and Management Sciences of the Polish Academy of Sciences is presented.

Approval Balloting for Fixed-Size Committees

- Business
- 2012

Approval voting is a well-known voting procedure for single-winner elections. Voters approve as many candidates as they like; a candidate wins if and only if no other candidate receives more…

Size approval voting

- Political Science, Computer ScienceJ. Econ. Theory
- 2009

It is shown in the axiomatic analysis that the family of all Size Approval Voting is characterized by a set of natural properties.

Computational Aspects of Multi-Winner Approval Voting

- Computer ScienceMPREF@AAAI
- 2014

The computational complexity of computing a best response for both a single agent and a group of agents is examined, showing that it is NP-hard for an agent or agents to compute how to vote given a fixed set of approval ballots of the other agents.