Post Election Audits

Shasta County is committed to full transparency to uphold the integrity of elections. We complete post-election audit during the official canvass of each election where a voting system is used. These audits are conducted in public and open to observation.

There are two types of post-election audits that are allowed by California Elections Code, a 1% Manual Tally and a Risk-Limiting Audit.  Shasta County always completes a 1% Manual Tally for each election. As part of the approved California Pilot Program, we are piloting a Risk-Limiting Audit (RLA).


What is the difference between a 1% manual tally and a risk-limiting audit:

  • 1% Manual Tally: Elections officials conduct a public manual tally of 1% of all ballots tabulated on a voting system during an election, including vote-by-mail ballots. This is a public process of manually tallying votes in 1% of the precincts, selected at random by the elections official, and in one precinct for each race not included in the randomly selected precincts. This procedure is conducted during the official canvass to verify the accuracy of the automated count. In a regular election year, counties hand count tens of thousands of ballots as part of the 1% manual tally. This process does not provide statistical evidence that the machine tally found the true winner for each contest on the ballot. This process also does not describe what should be done if the results of the manual tally do not agree with the election results. (See, Elec. Code, § 15360.)
  • Risk-Limiting Audit: Elections officials manually tally randomly selected ballots, stopping as soon as it is implausible that a full recount would show a different result than the ballots reviewed. As long as it is statistically plausible that a full recount would overturn the result, the risk-limiting audit continues to examine more ballots. Risk-limiting audits determine precisely how much hand-counting is necessary to confirm election results to a given level of confidence. The closer the contest, the more ballots that must be examined to have strong evidence – because fewer errors can change the outcome. The higher the desired confidence (e.g., 99% versus 90%), the more ballots that must be examined – because higher confidence requires more evidence. State law requires a 5% risk limit, or 95% confidence in the result of the election reported by the voting system. (See, Elec. Code, § 15367).


1% Manual Tally

During the official canvass of every election in which a voting system is used, the official conducting the election shall conduct a public manual tally of the ballots tabulated by those devices cast in 1 percent of the precincts chosen at random by the elections official. If one percent of the precincts should be less than one whole precinct, the tally shall be conducted in one precinct chosen at random by the elections official.

In addition to the one percent count, the elections official shall, for each race not included in the initial group of precincts, count one additional precinct. The manual tally shall apply only to the race not previously counted.

Additional precincts for the manual tally may be selected at the discretion of the elections official. (CA Elections Code Sec. 15360)

Method of Selecting the Random Sample

To select the precincts, a report is generated from our voter registration database that randomly selects a precinct and then displays the contests listed.  After the pull of that list, slips of paper in equal size with one slip per precinct are folded and placed in a hat and shuffled.  A random number is drawn from the hat.  This is continued until we have enough precincts that cover each voting system tabulation type and each contest within the election.  While the statute mandates only 1% of the total precincts are to be audited, we may select more for additional transparency.

Procedure for the Manual Tally — Audit Board

After the precincts for the manual tally are selected, one or more boards of four people hand counts each contest using tally sheets.


Risk-Limiting Audits (RLA)


A risk-limiting audit is a method of ensuring that election results match voter selections reflected on paper ballots.

The risk-limiting audit (RLA) is a procedure that provides strong statistical evidence that the election outcome is correct, or has a high probability of correcting an outcome that wouldn’t match a full hand count of the ballots. The audit itself requires human beings to examine and verify more ballots in close contests and fewer ballots in contests with wider margins.

In California, when a risk-limiting audit is used, it must confirm that the election results reported by the voting system are 95% likely to be accurate. Unlike the post-election 1% manual tally traditionally used to confirm election results in California, under a risk-limiting audit every ballot cast in the election—regardless of which precinct it was cast in—has an equal chance of being audited.

The following flowchart shows how risk-limiting audits are conducted:

risk limiting audit flow chart


California Pilot Program

In 2018, Assembly Bill (AB) 2125 authorized a risk-limiting audit pilot program that will remain in effect until January 1, 2021.  Under AB 2125 and beginning with the March 3, 2020, Presidential Primary Election, a county may optionally use risk-limiting audits in lieu of the 1% manual tally. (See, Elec. Code, §§ 15365-15367.)

On August 27, 2020, Governor Newsom signed Assembly Bill (AB) 2400 (Quirk, 2020) to make changes to the Risk Limiting Audits pilot program created by AB 2125 (Quirk, 2018). AB 2400 permits a county to conduct a risk-limiting audit on one or more contests fully contained in the county rather than all contests held in the county as was required under AB 2125; deletes the AB 2125 requirement to conduct partial risk-limiting audits for each cross-jurisdictional contest; and extends the sunset date of the pilot program from January 1, 2021 to January 1, 2023. These changes address concerns with AB 2125 raised by the working group the Secretary of State convened pursuant to AB 2125 and allows counties to participate in the pilot program without risking a full hand count.

The Secretary of State has promulgated regulations that implement and administer the risk-limiting audit pilot program. Those regulations can be found at:


Methods for ensuring ballot security and chain-of-custody

Ballot security and chain-of-custody for ballots is essential for ensuring that the ballots are secure and have not been tampered with. The following methods achieve these goals:

  • Ballot containers (bags, boxes, tubs, etc.) should be properly identified, signed, and sealed by at least two elections officials.
  • A chain-of-custody log should accompany every container, and seal numbers should be confirmed by elections officials at the ballot storage facility.
  • Elements of the chain-of-custody log may include the precinct ID, number of ballots in each container, and the tabulator ID. The same principles apply to voting equipment chain-of-custody.

Additional References