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Pilot audit of March presidential primary results showcases security, accuracy of Michigan elections systems

The results of a Risk-Limiting Audit (RLA) pilot conducted on the March 10 presidential primary results suggested their accuracy and security, and reinforced the state’s preparedness for elections in August and November. The pilot, in which 80 out of 83 counties participated, randomly sampled of ballots from 277 jurisdictions across the state. The exercise, the largest of its kind in the nation, was conducted as part of Secretary of State Jocelyn Benson’s ongoing efforts to work with local election officials to strengthen Michigan’s systems.

“The overwhelming participation from county and local clerks in this audit pilot underscores the hard work they do to safeguard our elections, and their dedication to public service,” said Secretary Benson. “Their commitment to ensuring accuracy in our results is one of the primary reasons Michiganders can continue to trust the outcome of our elections.”

The results of the 669 random ballots selected in the pilot mirrored the state’s official election results within one percentage point for the leading candidates in each primary, suggesting if an actual audit had been conducted the outcome of the election likely would have been confirmed within the statistical level of certainty selected. The audit pilot also reinforced the significance of paper ballots, which provide a key election security safeguard, allowing for the meaningful audit of election results to ensure outcomes are correct.

RLAs, considered the gold standard of post-election audits, provide an extra layer of security when partnered with the traditional audit methods already utilized by election officials. Clerks currently conduct random procedural audits in which all ballots in a given precinct are counted by hand to ensure accuracy. This RLA pilot, which built on smaller pilots in 2018 and 2019, was conducted with the assistance of VotingWorks, a nonprofit, nonpartisan organization. The pilot also drew upon the advice of the Election Security Advisory Commission and an audit task force composed of election clerks.

“The findings of this pilot provide an extra measure of confidence and an extra layer of security as we look ahead to August and November,” said Secretary Benson. “This reinforces not only that we’re ready for those elections, but that Michigan is a leader in utilizing state-of-the-art security measures to ensure the integrity of our systems.”

A report on the audit pilot results, along with the full data, is available on the website


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