Welfare Cost of Proportional Representation in Temporal Voting

A study on arXiv (2605.11157) quantifies the efficiency cost of enforcing proportional representation in temporal voting, where collective decisions are made repeatedly over a fixed horizon. The research measures the worst-case ratio between maximum utilitarian welfare and welfare achievable under proportionality axioms like justified representation (JR). Findings show that imposing proportionality leads to a growing but sublinear welfare loss as voters or rounds increase. A clear separation among axioms is identified, with JR incurring distinct costs.