Live fact-checking sounds as if it's impossible – but it's more of "a misnomer", says Aaron Sharockman, editor of PunditFact, a PolitiFact project.
While audiences might want to instantly know if a claim they see on TV is true or not, it's never that simple, but there can be "success with programmes that get really close".
Sharockman shared some of the lessons the PolitiFact team learned during their first live fact-check, speaking at the Global Fact-Checking Summit in London yesterday.
PolitiFact took up the challenge of live fact-checking the State of the Union address at the beginning of the year, as a hook for a Kickstarter campaign to raise funding.
Among the benefits of live fact-checking is making your organisation known, explained Sharockman.
"Events offer a great opportunity to raise your profile, to bring more people into the conversation," he said. "I think they are a great way to grow your audience."
PolitiFact plans to continue using the format for the US election campaign, but how do you pull off a live fact-check?
There's a three-point checklist for that. You need a place to host it, whether it's your Twitter feed or a liveblogging platform, people who are willing to sign up for the task, and a plan to do it quickly.
PolitiFact chose the liveblogging approach for the State of the Union address, working in teams of two reporters, with each team getting "about 10 minutes of speech" on rotation.
"We did really simple pre-homework", explained Sharockman, creating a cheat sheet of facts and resources based on the topics the team thought were going to be included in the speech.
"You have a pretty good sense of what people are going to talk about," he said, adding that they also had an embargoed copy of the speech a few minutes before the start.
It was a "very good first run for us because we had the speech ahead of time", he said, meaning there was no need to actually type the speech into the liveblog, but simply copy-paste from the document.
The team also rehearsed the process using the 2014 State of the Union speech, each fact-checker pressing play at the same time to see "how fast things move".
But despite the practice sessions and the prep ahead of time, elements that could have been better thought out or presented during the liveblog became clear with the benefit of hindsight.
In between sections of the president's speech, the team pulled in a related fact that was marked as false, but readers also associated the president's remarks in that section with the false verdict.
"We did make mistakes I think...We thought we were clear but you had this kind of 'yin and yang' happening," said Sharockman.