Percentage-based versus SAFE Vote Tabulation Auditing: A Graphic Comparison

Trustworthy elections require comprehensive auditing and corrective action to eliminate major errors in counting votes. In this paper, we address just one component of electoral audits: specifying how many randomly selected precincts should undergo hand recounts to decide whether the winner in the electronic tally should be confirmed. Several pending electoral-integrity bills specify hand audits of between 2 and 10 % of all precincts. However, percentage-based audits are usually inefficient, because they use large samples for large jurisdictions, even though the sample needed to achieve good accuracy is much more affected by the closeness of the race than the size of the population. Percentage-based audits can also be ineffective, since close races may require auditing a large fraction of the total – even a 100 % hand recount – to provide confidence in the outcome. This paper presents the SAFE (Statistically Accurate, Fair and Efficient) alternative to percentage-based sampling, based on the same statistical principles that inform audits in business and finance. In recent federal elections, highly reliable SAFE audits would have required about the same total effort and resources as the percentage-based audits now being considered. However, SAFE audits can ensure equally high confidence in all electoral outcomes by using auditing resources more efficiently and employing large samples only when necessary