A holistic analysis of participatory budgeting

Participatory Budgeting is a relatively new democratic tool that allows citizens to influence the way a city spends its budget. It was invented in Brazil in the 1990s and has since spread around the world. Nowadays, approximately 1500 cities use Participatory Budgeting to foster public participation in city politics and to reach a more equitable public spending. In the last few years, Participatory Budgeting has received growing attention from the scientific community. One area of research that, in particular, has received a lot of attention lately is the design of better voting rules for Participatory Budgeting. In most instances of Participatory Budgeting voters can indicate which projects they want to be funded and which projects they do not approve of. First, the most approved project is funded. Then, the next most approved project for which the remaining budget suffices is funded. This process continues until no further project can be funded. While this voting rule is intuitive and easy to understand, it has many disadvantages. In particular, it is very susceptible to the Tyranny of the Majority, i.e., 51 percent of the voters could decide on 100 percent of the budget. Considerable progress has been made in the last few years in designing voting rules that lead to better and fairer outcomes. However, this line of research has, until now, focused very narrowly on a single, isolated Participatory Budgeting instance. In this project, I want to consider a more holistic view of this problem. Indeed, in practice, Participatory Budgeting is usually not a singular event but repeated every year. It is also very often performed in many districts of a city separately at the same time. Finally, Participatory Budgeting is usually a two-stage process, where citizens can propose projects in a first stage before voting on the proposed projects in the second stage of the process. In this project, I will take all three of these characteristics into account in order to define better voting rules for Participatory Budgeting. In particular, the goal is to design voting rules that take the interaction between both stages of the Participatory Budgeting process into account and produce outcomes that, in the long run, are fair to all districts.

Today, the need for new forms of political participation for ordinary citizens is higher than ever in light of the record low levels of trust in politics and declining civic engagement. One of the most widespread and popular examples of democratic innovation is participatory budgeting (hereafter, PB), which allows citizens to decide how to allocate (parts of) cities' budget and which is used in thousands of cities world wide. Specifically in Europe, PB often takes the form of e-PB, where most of the participation happens online. Nevertheless, most cities use very simple, majoritarian voting rules for PB, that do not adequately represent minority opinions and which can lead to a "tyranny of the majority". In his project "A Holistic Analysis of Participatory Budgeting", Jan Maly studied the question how we can define and achieve proportional representation in PB. This way, his project could contribute to the recent spread of fair and representative voting rules for PB, like the so-called method of equal shares, which cities in Poland, Switzerland and the Netherlands have recently started using.