Colorado Secretary of State logo - cube with a C in it

Colorado
Secretary of State
Jena Griswold

Colorado Secretary of State logo - Colorado Secretary of State Jena Griswold

Picture of Secretary of State Jena Griswold

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Colorado Secretary of State logo - cube with a C in it

Colorado
Secretary of State
Jena Griswold

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Risk-Limiting Audit (RLA) FAQs

Q1. What is a risk-limiting audit?

A1. A risk-limiting audit is a post-election audit that gives a statistical level of confidence that the outcome of an election is correct. In other words, after performing a risk-limiting audit, we can say that there is a high probability that the reported winners accurately reflect how voters marked their ballots.

Q2. What is the risk-limit?

A2. The risk-limit tells us what chance the audit would have to correct a wrong outcome. An audit with a 5% risk-limit means that if an election has the incorrect reported outcome, on average 95 times out of 100 the audit would catch that incorrect outcome and correct it. If the reported outcome of the election is correct, then the audit confirms that outcome. Technical information on audit can be found on our risk-limiting audit resources page.

Q3. What kind of risk-limiting audits are there?

A3. Colorado has two types of risk-limiting audit: a comparison audit and a ballot-polling audit.

Counties that have the ability to export a cast vote record file from their voting system perform a comparison audit. Counties that do not have the ability to export a cast vote record file from their voting system perform a ballot-polling audit. Counties that count the votes by hand do not participate in the audit.

Q4. How does Colorado perform the audit?

A4. Comparison Audit

After all of the ballots have been tabulated, audit boards made up of county residents are tasked with finding a random sample of specific ballots and reporting the markings on that ballot. If what the audit board reports matches how the voting system tabulated the ballots, the audit concludes. If there are discrepancies, additional ballots are randomly selected to compare until the outcome has been confirmed. If the wrong outcome was reported eventually all of the ballots will be examined and a new outcome will be determined.

Ballot-Polling Audit

After all of the ballots have been tabulated, audit boards made up of county residents are tasked with finding a random sample of specific ballots and reporting the markings on that ballot. If a sufficient proportion of the sample conforms with the reported winner, the audit concludes. If not, additional ballots are randomly selected. If the wrong outcome was reported, eventually all of the ballots will be examined and a new outcome will be determined.

Q5. How are the ballots to audit chosen?

A5. Each county creates a ballot manifest that describes how many ballot cards have been counted, in terms of batches and the number of ballots in each batch. A pseudo-random number generator, with a random seed, is used to randomly select ballots from the ballot manifest.

Q6. How is the random seed generated?

A6. The random seed used in Colorado is a 20-digit string of numbers. A set of 20 ten-sided dice are rolled during a public meeting to generate the number string, which is then recorded and posted on the audit center.

Q7. What is the difference between a ballot and a ballot card?

A7. A ballot card is a page of the ballot that has two sides. A ballot may consist of one, two, or more ballot cards. For the RLA this is an important distinction because the cast vote record will have a separate row for each ballot card, not one row for each set of ballot cards. Therefore, the number of ballot cards can be much greater than the number of ballots cast in a county.

Q8. Why does Colorado conduct a risk-limiting audit?

A8. In 2009, the Colorado General Assembly began the process of requiring the implementation of risk-limiting audits by enacting 1-7-515, C.R.S. The first audit was delayed a few years as technology caught up to the task. In the 2017 Coordinated Election, all of the counties that use machines to tally votes performed the first statewide risk-limiting audit.

Q9. How can I get involved with the audit?

A9. Since the audit is performed at the county level, you can contact your County Clerk and Recorder's office to get involved in the next audit. If you're interested in reports from former audits, you can go to the Secretary of State's audit center.