Arlo is a secure tool for conducting Risk-Limiting Audits (RLAs) used by 11 states. It was developed by VotingWorks with support from the U.S. Department of Homeland Security.
The code for Arlo is open-source and freely available for anyone to use. VotingWorks optionally provides hosting and support to states and local jurisdictions.
A risk-limiting audit examines a random sample of paper ballots, comparing them to the machine count to ensure that the winner actually won.
The number of votes needed to manually count depends on the margin of victory. The closer the margin, the more votes we manually count. The RLA confirms that, if a full hand-tally were performed, it would give the same outcome.
Running a risk-limiting audit can vary from state to state, depending on the proportion of mail ballots and the type of scanning equipment used.
Arlo is flexible and supports any jurisdiction as long as there are paper ballots. Arlo supports ballot polling, batch comparison, ballot comparison, or hybrid audit methods.
In addition to software, VotingWorks provides planning, training, and support for jurisdictions conducting risk-limiting audits.