In the context of election security, a Risk-Limiting Audit (RLA) is a statistical framework that uses a minimal partial recount of the ballots to guarantee that the results of the election were correctly reported. A generalized RLA framework has remained elusive for algorithmic election rules such as the Single Transferable Vote (STV) rule, because of the dependence of these rules on the chronology of eliminations and elections leading to the outcome of the election. This paper proposes a new graph-based approach to audit these algorithmic election rules, by considering the space of all possible sequences of elections and eliminations. If we fix a subgraph of this universal space ahead of the audit, a sufficient strategy is to verify statistically that the true election sequence does not leave the fixed subgraph. This makes for a flexible framework to audit these elections in a chronology-agnostic way.
翻译:在选举安全领域,风险限制审计(RLA)是一种统计框架,通过对选票进行最小化的部分重新计票,以保证选举结果的正确性。对于单记可让渡投票(STV)等算法化选举规则,由于这些规则依赖于导致选举结果的淘汰与当选顺序的时间序列,通用的RLA框架一直难以建立。本文提出一种新的基于图的方法来审计这类算法化选举规则,该方法通过考虑所有可能的当选与淘汰序列空间来实现。若在审计前固定该全局空间的某个子图,则只需通过统计方法验证真实选举序列未离开该固定子图,即可构成充分的审计策略。这为以时序无关的方式审计此类选举提供了一个灵活的框架。