Tyranny of the Minority in Social Choice: a Call to Arms

The vast majority of research in social choice theory, be it axiomatic characterizations, welfare bounds, or equilibrium analysis, makes the implicit assumption that the entire affected population votes. However this ideal description is very far from the situation in practice, and even more so in the age of online voting and various direct democracy initiatives-often, a handful of avid voters effectively make the decisions for the silent majority. Our starting point is that abstention and partial participation are not a curious exception but the norm. We therefore argue that models of abstention should be given at least as much attention (if not more) as models of strategic behavior, and theoretical properties of voting rules such as welfare and fairness guarantees must be evaluated in light of such models in order to be relevant. To that end, we call the multiagent systems research community to design more effective tools to better handle both causes and effects of low participation; and highlight promising directions.