San Francisco Ballot Image Audits
CitizensOversight (2026-11-11) RayLutz
This Page:
copswiki.org/Common/M2069
More Info: ElectionAudits
San Francisco Ballot Image Audits
From AuditEngine.
Updated 2026-11-11.
Citizens' Oversight audits San Francisco elections from their ballot images, with AuditEngine. AuditEngine reads each ballot image on its own. It then compares its reading with the cast vote record (CVR), one ballot at a time.
This page gives the state of each San Francisco audit, and links its reports. Some audits are being run again. The first reports are kept here unchanged, so they can be compared with any amended report.
Status
| Election | Scope | State | Reports |
|---|---|---|---|
| 2024 General | Sheet 1 of every ballot, all 11 districts | Report issued. A study of batches scanned twice is under way. An amended report is planned. | First report, frozen copy. Live reports |
| 2024 General | District 5, the pilot | Report issued. The sheet 1 audit includes District 5 and takes its place. | First report, frozen copy. Live reports |
| 2024 General | Every sheet of every ballot | Paused at mapping. The county does not publish ballot style masters. | None |
| 2020 Primary | Every ballot | Job set up only. No audit report. | None |
The live reports change each time an audit is run again. The attached copies do not change.
The 2024 General Election audit
San Francisco uses a voting system from Dominion Voting Systems. Its ballots had up to four sheets. The audit reads sheet 1 of every ballot, which holds the contest for President.
- 412,351 ballot sheets were audited, with 3,878,114 ballot-contests.
- AuditEngine and the CVR agree in 99.6% of ballot-contests, with no variation of any kind.
- 1,575 ballot-contests disagreed after the county's adjudication, or 0.04%.
- 12,617 sheets were printed by ballot marking devices. AuditEngine read their printed text, which the voter can read, not their barcodes.
- The contest with the most variation compared with its margin is Member, Board of Education. It has 2,537 contest variants and a margin of 248 votes, with 177 disagreed.
Batches scanned twice
The audit found nine pairs of batches that hold the same ballots. Each pair is one set of paper scanned twice.
- A person compared the two images of sample ballots in each pair. All nine pairs are confirmed.
- In six pairs, both batches have CVR records. Those 335 ballots are counted twice in the CVR.
- In three pairs, one batch has no CVR records. Those images are extra, but the ballots are not counted twice.
| Batch a | Batch b | Ballots | Both in the CVR |
|---|---|---|---|
| 00035_00092 | 00912_00000 | 100 | yes |
| 00035_00058 | 00813_00000 | 74 | yes |
| 00035_00065 | 00601_00000 | 70 | yes |
| 00035_00064 | 00752_00000 | 54 | yes |
| 00001_00765 | 00001_00802 | 26 | yes |
| 00011_00567 | 00011_00568 | 11 | yes |
| 00035_00170 | 00995_00000 | 70 | no |
| 00035_00169 | 00995_00000 | 27 | no |
| 00014_01677 | 00014_01694 | 21 | no |
Four of the six pairs counted twice come from tabulator 35, a central scanner. Those batches hold card 1 of each ballot only. So 298 ballots have card 1 counted twice, and their other cards once. In the other two pairs, 37 ballots were scanned again whole, all four cards.
For President, the audit counts 412,197 ballots from the images. Removing the repeats leaves 411,862. The CVR has 412,121. Whether any contest's margin is close enough to matter is not yet checked.
Why the usual checks miss it
California's 1% manual tally draws batches at random, then counts their paper by hand. A batch scanned twice is one stack of paper, but two batches in the voting system. If the tally draws the repeat, its paper may not be found under that batch number. A missing box is easy to put down to a records error, and another batch is drawn in its place. If the tally draws the original, its paper is found and its count matches. So a batch that cannot be found is a warning sign. It should be explained, not replaced.
The CVR totals agree with the official results, because both hold the repeats. A batch-by-batch check of the ballot manifest against the CVR can flag an extra batch. It does not say which batch the extra one repeats, or prove that the two are the same paper.
A ballot image audit pairs the two scans by their votes, ballot by ballot. A person then confirms each pair from the images. That names both batches, and the ballots counted twice.
What the amended report will add
- A section on the batches scanned twice, with the pairs and their effect on each contest.
- Counts with the repeats taken out.
- Any correction found while the audit is run again.
The first report stays attached here, unchanged.
Change log
- 2026-11-11: Page created. The nine pairs of batches are confirmed. The amended report is not yet issued.