Secretary of State Jena Griswold on Friday directed county clerks to begin the audit of a random selection of ballots after this month’s general election.

A press release said that this risk-limiting audit, the only statewide one in the country following most elections, provides a “high statistical level of confidence that the outcome of an election is correct and reflects the will of the voters.”

Colorado conducted its first statewide audit in 2017, covering all counties that used machines to tally their votes.

Two counties, Jackson and San Juan, do not perform an audit because their ballots are hand counted.

The secretary of state’s office randomly chose the ballots for each clerk to review using a 20-digit number, generated from multiple rolls of a 10-sided die.

“If what the audit board reports matches how the voting system tabulated the ballots, the audit concludes,” Griswold’s website explains. “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.”

The risk limit is set at 5%, meaning that if an election result was reported erroneously, the audit would catch the error with 95% certainty.

“What distinguishes a risk-limiting audit is it has a large, pre-specified chance of correcting the outcome if the outcome is wrong,” Philip Stark, who designed an system, told The Colorado Statesman in 2014. “These don’t just do a quick spot-check of the function of machines and then stop; instead, they keep looking at more and more evidence until you have convincing statistical evidence that if you keep looking at more, you’re just going to confirm the answer that you’ve already got.”

Washington County Clerk and Recorder Annie Kuntz, whose audit occurred on Friday, described performing the audit every election for the past few years.

“One judge reads the answers, how the person voted. And the other judge enters it into the database,” she said. “It probably took 10, 15 minutes.”

Kuntz called the process “pretty painless.” From a county of 1,790 voters, she had only 11 ballots to review.