A risk-limiting audit is a type of post-election audit, during which a random sample of ballots is selected and the selections on the ballots are compared to the electronic "cast vote record" inside a voting machine. In a decisive contest, a small sample of ballots can be audited, while a close race will require a comparatively larger sample.
What is a risk-limiting audit?
A risk-limiting audit, or RLA, is a post-election audit designed to provide a specified statistical limit on the risk of certifying the wrong electoral outcome. It examines a random sample of voter-verifiable paper records and can expand the sample, potentially to a full hand count, when the evidence is not strong enough.
How does a risk-limiting audit work?
An RLA selects ballots or batches using a documented random process, manually interprets the sampled paper records, and compares the evidence with the reported outcome using a statistical method. If the sample provides sufficient evidence, the audit can stop; if not, more ballots are examined until the risk limit is met or a full count occurs.
Does an RLA require paper ballots?
An RLA needs trustworthy voter-verifiable paper records that can serve as evidence of voter intent. Those are commonly voter-marked paper ballots or voter-verified paper records. A purely paperless voting system cannot support a paper-based RLA because there is no independent physical record to sample and manually inspect against the reported outcome.
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High consensus
A risk-limiting audit is a type of post-election audit, during which a random sample of ballots is selected and the selections on the ballots are compared to the electronic "cast vote record" inside a voting machine. In a decisive contest, a small sample of ballots can be audited, while a close race will require a comparatively larger sample.
Cite this term
Election Security Glossary. (2026). Risk Limiting Audits (rlas). In Election Security Glossary. Retrieved August 21, 2026, from https://electionsecurityglossary.com/glossary/risk-limiting-audits-rlas
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