Post-Election Audits
In Washington, each county conducts a post-election audit after every election.
There are two types of post-election audit conducted in Washington:
Random Batch Audit
A random check of ballot counting equipment, commonly known as a random batch audit, compares a hand count of ballots to the voting system count in selected batches or precincts. This check occurs within 48 hours of election day. (RCW 29A.60.170)
Random Ballot Audit
A random ballot audit, also known as a risk-limiting audit (RLA), uses statistics to confirm election outcomes. This check helps verify that the apparent winner of an election actually won.
Ballots are randomly selected for review, then compared to the voting system record until enough have been sampled to confirm that the correct winner was found. If the winner won by a lot of votes, the sample needed to confirm the outcome may be quite small; if the race was close, the audit will examine more ballots.
The risk limit for statewide ballot comparison risk-limiting audits (RLAs) is 5%.
The risk limit for county-level ballot comparison RLAs is 5%.
2025 February Special Election Random Ballot Audits
| Counties | Audit Date | Target Contest | Audit Report |
|---|---|---|---|
| Benton | 02/18/2025 | Kiona-Benton City School District 52 Proposition No. 1 | Audit Board Report |
| Cowlitz | 02/18/2025 | Castle Rock School District No. 401 Proposition 1 | Audit Board Report |
| Snohomish | 02/18/2025 | Lake Stevens School District No. 4 Proposition No. 1 | Audit Board Report |
| King | 02/19/2025 | Seattle School District No. 1 Proposition No. 1 | Audit Board Report |
| Mason | 02/19/2025 | North Mason School 403 Renewal Of Educational Programs And Operations Levy | Audit Board Report |
Random seed dice roll: https://youtube.com/live/B2bDKb3Lbuw?feature=share
Random seed: 13615374355548269914
Archived Audits
Random ballot audit software certification
Arlo Approval for Use - Certification.pdf
Additional resources
RCW 29A.60.185 - Audit of results.
WAC Chapter 434-261 - Sections 114-119 on risk-limiting audit procedures.
risklimitingaudits.org - Additional resources and RLA academic papers