Proportionally Representative Participatory Budgeting: Axioms and Algorithms

TL;DR

This paper introduces axioms and algorithms for proportional representation in participatory budgeting, focusing on approval elections to ensure budgets reflect diverse voter demands.

Contribution

It generalizes approval-based multi-winner election axioms to participatory budgeting and explores the computational complexity of finding such representative budgets.

Findings

Proposes new proportional representation axioms for participatory budgeting

Identifies computational complexity results for finding proportional budgets

Develops algorithms satisfying the proposed axioms

Abstract

Participatory budgeting is one of the exciting developments in deliberative grassroots democracy. We concentrate on approval elections and propose proportional representation axioms in participatory budgeting, by generalizing relevant axioms for approval-based multi-winner elections. We observe a rich landscape with respect to the computational complexity of identifying proportional budgets and computing such, and present budgeting methods that satisfy these axioms by identifying budgets that are representative to the demands of vast segments of the voters.