Paper ID: 2407.18092

Strategic Cost Selection in Participatory Budgeting

Piotr Faliszewski, Łukasz Janeczko, Andrzej Kaczmarczyk, Grzegorz Lisowski, Piotr Skowron, Stanisław Szufa

We study strategic behavior of project proposers in the context of approval-based participatory budgeting (PB). In our model we assume that the votes are fixed and known and the proposers want to set as high project prices as possible, provided that their projects get selected and the prices are not below the minimum costs of their delivery. We study the existence of pure Nash equilibria (NE) in such games, focusing on the AV/Cost, Phragm\'en, and Method of Equal Shares rules. Furthermore, we report an experimental study of strategic cost selection on real-life PB election data.

Submitted: Jul 25, 2024