When Diversity in Voting Trumps Ability

Abstract Would you prioritize assembling a group of more competent individuals or a more diverse group? According to the well-known Diversity-Trumps-Ability Theorem (DTA), when two groups of similar size are compared, the more diverse group generally outperforms the more competent group. Despite considerable criticism regarding the DTA’s mathematical rigor, it has sparked substantial interdisciplinary discussion. While most research on the DTA focuses on its implications within specific fields or on empirical simulations to test its validity, we aim to establish precise conditions under which diversity indeed surpasses ability in a particular decision-making context: voting. To this end, we integrate the DTA into a voting model inspired by the Condorcet Jury Theorem (CJT) and model diversity based on the classic dependency model in the CJT literature, namely the influence of an opinion leader .