Ballotlevel

Ballotlevel, or ballot-level, refers to processes and analyses conducted at the level of individual ballots rather than aggregates. In the context of elections, ballot-level audits examine the correspondence between each paper ballot and its digital representation, such as cast vote records (CVRs) or ballot images, to verify that the reported outcome reflects voter intent.

In practice, ballot-level audits come in two main forms. Ballot-level comparison audits compare a randomly selected sample of ballots with their corresponding CVRs or digital tallies, using the ballot as the ground truth to verify accuracy. Ballot-level ballot-polling audits sample ballots without requiring a direct ballot-to-CVR linkage, instead inferring overall accuracy from the sampled ballots. Many risk-limiting audits (RLAs) can be implemented at the ballot level, designed to stop and correct the outcome as soon as confidence reaches a predetermined risk limit.

Requirements for ballot-level auditing include verifiable paper records (paper ballots or ballot images) and a transparent chain of custody, along with a reliable mapping between ballots and records. A ballot manifest lists all ballots in a precinct, enabling random sampling and traceability.

Advantages of ballot-level audits include providing direct, ballot-by-ballot evidence of accuracy and the ability to correct incorrect outcomes with high probability, which supports public trust and auditability. Challenges include resource intensity, dependence on the availability and integrity of ballot images or CVRs, and privacy considerations when scrutinizing individual ballots publicly.

Standards and implementation guidance come from election-technology bodies and officials, with ballot-level approaches increasingly adopted in jurisdictions seeking robust post-election verification and transparency.