Proxy Selection in Transitive Proxy Voting

TL;DR

This paper introduces a formal model of liquid democracy, analyzes its axiomatic properties, and investigates manipulation, revealing that proxy voting can be more susceptible to manipulation than traditional voting.

Contribution

It presents a new formal model of liquid democracy, proves an analogue of May's Theorem, and analyzes manipulation in proxy voting.

Findings

Proposes a formal model of liquid democracy with richer proxy selection.

Establishes an analogue of May's Theorem for proxy votes.

Shows manipulation occurs more frequently in proxy voting than in classical voting.

Abstract

Transitive proxy voting (or "liquid democracy") is a novel form of collective decision making, often framed as an attractive hybrid of direct and representative democracy. Although the ideas behind liquid democracy have garnered widespread support, there have been relatively few attempts to model it formally. This paper makes three main contributions. First, it proposes a new social choice-theoretic model of liquid democracy, which is distinguished by taking a richer formal perspective on the process by which a voter chooses a proxy. Second, it examines the model from an axiomatic perspective, proving (a) a proxy vote analogue of May's Theorem and (b) an impossibility result concerning monotonicity properties in a proxy vote setting. Third, it explores the topic of manipulation in transitive proxy votes. Two forms of manipulation specific to the proxy vote setting are defined, and it is shown that manipulation occurs in strictly more cases in proxy votes than in classical votes.