Assertion-based approaches to auditing complex elections, with application to party-list proportional elections

Michelle Blom, Jurlind Budurushi, Ronald L. Rivest, Philip B. Stark, Peter J. Stuckey, Vanessa Teague, Damjan Vukcevic

Research output: Chapter in Book/Report/Conference proceedingConference PaperResearchpeer-review

4 Citations (Scopus)


Risk-limiting audits (RLAs), an ingredient in evidence-based elections, are increasingly common. They are a rigorous statistical means of ensuring that electoral results are correct, usually without having to perform an expensive full recount—at the cost of some controlled probability of error. A recently developed approach for conducting RLAs, SHANGRLA, provides a flexible framework that can encompass a wide variety of social choice functions and audit strategies. Its flexibility comes from reducing sufficient conditions for outcomes to be correct to canonical ‘assertions’ that have a simple mathematical form. Assertions have been developed for auditing various social choice functions including plurality, multi-winner plurality, super-majority, Hamiltonian methods, and instant runoff voting. However, there is no systematic approach to building assertions. Here, we show that assertions with linear dependence on transformations of the votes can easily be transformed to canonical form for SHANGRLA. We illustrate the approach by constructing assertions for party-list elections such as Hamiltonian free list elections and elections using the D’Hondt method, expanding the set of social choice functions to which SHANGRLA applies directly.

Original languageEnglish
Title of host publication6th International Joint Conference, E-Vote-ID 2021 Virtual Event, October 5–8, 2021 Proceedings
EditorsRobert Krimmer, Melanie Volkamer, David Duenas-Cid, Oksana Kulyk, Peter Rønne, Mihkel Solvak, Micha Germann
Place of PublicationCham Switzerland
Number of pages16
ISBN (Electronic)9783030869427
ISBN (Print)9783030869410
Publication statusPublished - 2021
EventInternational Conference on e-Voting and Identity 2021 - Online, Switzerland
Duration: 5 Oct 20218 Oct 2021
Conference number: 6th (Proceedings)

Publication series

NameLecture Notes in Computer Science
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


ConferenceInternational Conference on e-Voting and Identity 2021
Abbreviated titleE-Vote-ID 2021
Internet address


  • D’Hondt method
  • Hamiltonian methods
  • Party-list proportional elections
  • Risk-limiting audits

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