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arXiv · 2206.14605

Auditing Ranked Voting Elections with Dirichlet-Tree Models: First Steps

Floyd Everest·Michelle Blom·Philip B. Stark·Peter J. Stuckey·Vanessa Teague·Damjan Vukcevic
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Abstract

Ranked voting systems, such as instant-runoff voting (IRV) and single transferable vote (STV), are used in many places around the world. They are more complex than plurality and scoring rules, presenting a challenge for auditing their outcomes: there is no known risk-limiting audit (RLA) method for STV other than a full hand count. We present a new approach to auditing ranked systems that uses a statistical model, a Dirichlet-tree, that can cope with high-dimensional parameters in a computationally efficient manner. We demonstrate this approach with a ballot-polling Bayesian audit for IRV elections. Although the technique is not known to be risk-limiting, we suggest some strategies that might allow it to be calibrated to limit risk.

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Floyd Everest, Michelle Blom, Philip B. Stark, Peter J. Stuckey, Vanessa Teague, Damjan Vukcevic. 2022-06-29. Auditing Ranked Voting Elections with Dirichlet-Tree Models: First Steps. https://doi.org/10.15157/diss%2F021

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