Risk-Limiting Audits

A Risk-Limiting Audit (RLA) provides evidence that the computers counted the ballots accurately. They provide reassurance when outcomes are right, as well as protection against hacks and errors that could produce wrong results.

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About Risk-Limiting Audits

A risk-limiting audit (RLA) checks a random sample of voter-verifiable paper ballots, giving strong evidence to support the reported election results (or triggering a recount).

An RLA can stop as soon as it finds strong evidence that the reported outcome was correct. Or, if the reported outcome was wrong because ballots were miscounted, an RLA is very likely to lead to a full recount that corrects the outcome before the election results are certified. RLAs provide strong assurance that the final outcome matches the ballots cast. Contests with wide margins can be audited with very few ballots, freeing up resources for auditing closer contests, which generally require checking more ballots.

RLAs in U.S. Elections

RLAs have been piloted and used in U.S. elections for over a decade, since 2008. In 2017, after years of planning and testing, Colorado conducted the first statewide RLA. As required by law, the state continues to conduct RLAs after its elections. In June 2020, following rigorous pilots, Rhode Island became the second state to conduct a statewide RLA, with the help of Verified Voting and VotingWorks. A growing number of states are enacting legislation that provides for or requires RLAs to check election results. Visit our post-election audit map to see where RLAs are conducted.


Video: Understanding Risk-Limiting Audits

Our explainer video on risk-limiting audits is here!

What is a Risk-Limiting Audit?

Fundamentals of an RLA, including what is needed to conduct an RLA and how an RLA differs from other types of audits.

About Risk-Limiting Audit Pilots

RLA pilots are test runs for jurisdictions. Read more about how RLA pilots can lead to full RLAs.

Differences Between RLA Methods

Overview of three RLA methods: ballot-level comparison, batch comparison, and ballot polling.

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Audit FAQ Page

Answers to frequently asked questions about audits. Topics include legislation, implementation, and oversight.

Why Do a Risk-Limiting Audit?

RLAs strategically allocate resources while providing evidence- based assurance of contest outcomes.

RLAs avoid checking
ballots unnecessarily.

Risk-limiting audits base the number of ballots selected on the specifics of the contest. Contests with a wide margin can be audited with very few ballots, freeing up resources for closer contests. In general, risk-limiting audits can be conducted with a modest amount of effort.

RLAs are
statistically sound.

The American Statistical Association endorses and recommends risk-limiting audits. When risk-limiting audit procedures are followed, there is only a limited chance that an incorrectly reported outcome could go undetected.

RLAs are

There are different types of risk-limiting audits, all of which provide statistical accuracy and efficiency. RLAs can adapt to various kinds of voting systems, as long as there are voter-verified ballots to audit.

Contact Us

Please email audits@verifiedvoting.org if your jurisdiction would like to conduct an audit or to direct any questions to our audit team.

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