From Multiwinner Elections to Participatory Budgeting

Participatory budgeting, in which city residents decide directly on the distribution of their mutual funds, is gaining increased visibility and attention; e.g., this year the city of Paris uses such a system to decide on the allocation of ~100M Euros. The theoretical understanding of the elicitation methods and aggregation mechanisms to be used in participatory budgeting is, however, lacking. To explain the state of the art, I will first discuss recent progress within computational social choice regarding multiwinner elections, which can be viewed as a special case of budgeting. I will then discuss several aggregation methods for participatory budgeting and scientific tools to evaluate them.