Benefits of using the Method of Equal Shares
On these pages, we describe the benefits of using the Method of Equal Shares for participatory budgeting. Our discussion is mostly based on analyzing what would have happened in several real participatory budgeting elections if those cities had used the Method of Equal Shares instead of the standard voting method (which just selects the projects with the highest votes). We argue that the data suggests that the Method of Equal Shares leads to fairer and better election outcomes than the standard voting method, and that it better reflects the preferences of the voters. We also present theoretical arguments from the academic literature.
The main benefit of using the Method of Equal Shares is that it makes participatory budgeting more participatory: every voter counts, because every vote gets to decide over an equal share of the budget. In contrast, in the standard method, voters may have very different amounts of influence. This is an intuitive reason to prefer the Method of Equal Shares, but we also show that it leads to better election outcomes in several ways based on data analysis.
- Higher and more equal voter satisfaction. Our simulations on voting data from Warsaw shows that voters approve more winning projects on average if the Method of Equal Shares is used, that a larger fraction of voters approves at least one of the winning projects, and that voter satisfaction is more equally distributed across the population. [more]
- Reduce bias towards the most popular categories. Our simulation shows that the election outcomes of the standard method are systematically biased in favor of certain types of projects (for example, road and transit improvements) and against other types of projects (for example, education projects). The Method of Equal Shares reduces this bias, and thereby better reflects the entire population. [more]
- Mathematical fairness guarantees. The academic literature has shown that the Method of Equal Shares guarantees all groups of voters an appropriate amount of representation in the outcome. It also guarantees that projects will win as long as they receive a certain minimum amount of support. [more]
- Comparison with other voting systems for participatory budgeting. We compare the Method of Equal Shares against the standard voting system, against Majority Judgment (as used in Paris), and quadratic voting. [more]