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2024 Presidential Primary and General Election: Post-Election Automated Ballot Tabulation Audit


An independent, automated audit relies solely on the use of independent software to tabulate ballot images. The results from the independent tabulation are then compared to the tabulation results from the voting system. Any variances between the two tabulations are easily identified and resolved. For the 2024 Presidential Primary and General Elections, this office has contracted with Clear Ballot, a Boston-based elections technology company which offers the ClearAudit software product. ClearAudit is the only currently available, market-ready software product that can perform an independent automated post-election tabulation audit using ballot images from another voting system.

The post-election tabulation audit is conducted using ballot images. The use of ballot images allows elections officials to maximize the technological functions of the new voting system while minimizing human error and eliminating chain of custody issues by using securely stored ballot images, rather than voted paper ballots.  The use of ballot images removes the need for election officials to physically handle or count voted ballots unless a petition for recount or other judicial challenge is granted.

A discrepancy variance level of 0.5% was established for the post-election tabulation audit.  If there is a variance between the voting system results and the audit results greater than 0.5% in any given contest and the variance cannot be explained, additional auditing will be performed before the election results are certified.

Pre-Audit Tasks

To prepare for the post-election tabulation audit, SBE provide s Clear Ballot with:

  • PDF files of all ballot styles for all 24 counties;
  • Pre-election reports for all precincts showing no votes cast;
  • Information to assign ballot styles to precinct; and
  • Files needed to process ballots used with the ExpressVote ballot marking device.

Upon receipt of the data, Clear Ballot:

  • Creates a Ballot Definition Files for each county;
  • Validates each Ballot Definition File; and
  • Creates a ClearAudit database for each county.

Audit Process

The local boards of elections send to Clear Ballot the images of ballots cast during early voting, on election day, and canvassed during the first mail-in ballot canvass. Once Clear Ballot receives the ballot images, Clear Ballot:

  • Transfers the ballot images from each county into its corresponding audit database;
  • Tabulates the ballot images from election day and early voting;
  • Resolves unreadable ballots;
  • Performs an audit database review; and
  • Sends a Preliminary Statement of Votes Cast to SBE.

Once SBE receives the Preliminary Statement of Votes Cast, SBE provides Clear Ballot with election results from early voting, election day, and the mail-in ballot 1 canvass. The Mail-in Ballot 1 Canvass includes all mail-in ballots that are canvassed through 12 p.m. on the Friday following election day. This is Phase 1 of the audit. The delay in sending the Phase 1 results to Clear Ballot is intentional. It creates a “blind” audit, meaning that Clear Ballot provides its results without knowing the results from the voting system. Clear Ballot uses the results from Phase 1 to create various reports comparing the sets of results.

After all the mail-in ballots and provisional ballots have been counted, the local boards of elections send to Clear Ballot the images of all ballots cast in the election. This is Phase 2. Clear Ballot adds the remaining images of mail-in ballots and all provisional ballots into the appropriate database, tabulates the ballot images, resolves unreadable ballots, and generates a new Comparison of Votes Cast that includes all ballots cast in the election.

Reports Produced by Clear Ballot

With this audit solution, election officials and other interested individuals can sort contest, ballot and precinct reports, see images of contests and ballots, and provide detailed information about how each ballot image was adjudicated. Clear Ballot produces for each county four audit reports.

  • Comparison of Cards Cast for each canvass: This report compares the number of ballots counted on election day, during both mail-in canvasses, and during the provisional canvass against the number of ballots tabulated by Clear Ballot.  This ensures that the same number of ballots were tabulated by both systems.1 
  • Comparison of Cards Cast by Precinct: This report compares the number of ballots cast in each precinct against the number of ballots tabulated during the audit.  This is another way to ensure that the same number of ballots are tabulated by both systems.1
  • Comparison of Votes Cast: This report compares the results from the voting system against the audit results and identifies possible discrepancies by candidate or choice. 
  • Contest Vote Discrepancy Threshold Report: This report shows - by contest - the number of vote differences between the two systems and the vote difference as a percentage. SBE has determined that a percentage of 0.5% or higher would trigger an additional review, which could include a manual review of voted paper ballots.2

2024 Presidential Primary Election Audit Results

The 2024 Presidential Primary Election took place on May 14, 2024. The audit reports produced by Clear Ballot for Phase 1 and Phase 2 will appear below.

1There is a known difference in how the voting system and Clear Ballot tabulate individual ballots. The voting system reads each ballot scanned, regardless of the number of pages, as 1 ballot. Clear Ballot, however, tabulates each page of a ballot as 1 card in both cards cast reports. Therefore, the total number of cards cast in a multi-page ballot as calculated by Clear Ballot will be greater than the total number of ballots cast as reported by the voting system.
2 There is a known difference in how the voting system and Clear Ballot tabulate write in votes in a contest where the voter votes for more than one candidate. Due to this difference, the vote discrepancy in these contests is sometimes higher than the threshold. In order to combat false discrepancies as a result of this difference in tabulation, there are two versions of the Contest Vote Discrepancy Threshold Report- one with write-ins, and one without. For the purposes of determining if a vote discrepancy is over the threshold, the version without write-ins is used.


Clear Ballot produces a public portal where ballot images from the primary and general election can be viewed. Click the link to go to the front page of the portal, where you can first read an article and watch a video explaining the portal’s capabilities. You can also click HERE view the ballot images from the 2022 Gubernatorial Primary Election directly. The ballot images from the 2024 Elections will be ready approximately 6-8 weeks after the election.