A Risk-Limiting Audit In Denmark: A Pilot

The theory of risk-limiting audits is well-understood, at least mathematically. Such audits serve to create confidence in the reported election outcome by checking the evidence created during the election. When election officials introduce election technologies into the voting process, it is best to do this after the appropriate auditing framework has been implemented. In this paper, we describe our experiences with piloting a risk-limiting audit of a referendum that was held in Denmark on December 3, 2015. At the time of the publication of this paper, Denmark’s election law did not permit electronic voting technologies to be used during voting allowing us to study auditing in isolation.
Our findings are that (1) risk-limiting audits also apply to paper and pencil elections; (2) election officials usually support risk-limiting audits even if no voting technologies are used because these audits can improve the efficiency of the manual count; (3) that practical and organizational challenges must be overcome to keep audits repeatable, in particular it must be possible to identify individual ballots repeatedly and reliably; (4) it is possible to arrange an audit for the result of an earlier stage in a count during a later stage, for example, an audit of the rough count results fine count; and (5) that whenever the electronic voting technologies are considered, auditing should be considered as part of feasibility study.