Combining diversity and excellence in multiwinner elections

We address the problem of electing a committee subject to diversity constraints. Given a set of candidates and a set of voters, such that each voter is represented by a linear order, the goal is to select a fixed-size subset of candidates by combining the excellence of candidates and a given form of diversity requirements. The grounding assumption in this paper is that the set of candidates is slotted into at least two groups according to a specific attribute such as gender, religion, ethnicity, or profession, and the diversity constraint takes the form of a vector of integers specifying the lowest number of candidates required from each group. We introduce a class of voting rules suitable for electing a diverse committee in this framework and we show how this class of rules handles the issue of combining both excellence and diversity. Furthermore, we provide some axiomatic properties that highlight the behavior of these rules when we aim to select a diverse committee.