Shortlisting Rules and Incentives in an End-to-End Model for Participatory Budgeting

TL;DR

This paper presents an end-to-end social choice model for participatory budgeting, analyzing shortlisting rules and strategic incentives for participants in proposing and voting on projects.

Contribution

It introduces a novel integrated model for participatory budgeting that considers both proposal shortlisting and voting, with a focus on strategic behavior incentives.

Findings

Analysis of various shortlisting rules and their normative properties

Insights into strategic incentives influencing participant behavior

Algorithmic evaluation of proposed rules

Abstract

We introduce an end-to-end model of participatory budgeting grounded in social choice theory. This model accounts for both the first stage, in which participants propose projects to be shortlisted, and the second stage, in which they vote on which of the shortlisted projects should be funded. We introduce several shortlisting rules for the first stage and we analyse them in both normative and algorithmic terms. Our main focus is on the incentives of participants to engage in strategic behaviour, especially in the first stage, in which they need to reason about how their proposals will impact the range of strategies available to everyone in the second stage.