The global growth in fact-checking has been driven by a boom in digital initiatives. Of the 45 fact-checkers surveyed ahead of the Third Global Fact-Checking Summit in Buenos Aires next week, only three publish their content primarily on television.

Yet even in the age of Snapchat and Facebook live, television matters.

Generally speaking, television audiences are larger than those fact-checking websites can muster. A successful online fact check may reach tens or even hundreds of thousands of pageviews — a TV audience is often in the millions. Older viewers, unlikely to access a fact check online, usually do watch television. And if a correction is made live during a debate or an interview, it will reach the same audience as the misleading claim: not an irrelevant feat in an era of social media echo chambers.

Just as important: Contracts with television networks to provide fact-checking services can be a fundamental source of revenue.

However, even in countries like the United States, where online fact-checking reaches wide audiences, lying politicians get a relatively free pass on television. This has real consequences that require fact-checkers to adapt their online work to the analog format.

Fact-checkers' transition into television can be hampered by an imperfect "translation" of online content into a script for television. Patrick Worrall, a fact-checker at Channel 4 News Fact Check says his team ran into early trouble making the leap to TV.

"The mistake we made originally was to have the writer of a long FactCheck blog try to 'boil down' their own work into a shorter version," Worrall said. "Now we use a TV specialist to take a blog post and rewrite it [...] So almost everything will be different from the corresponding blog post: the structure, phrasing, avoidance of technical jargon, even the 'killer' fact(s) that we focus on."

What fact-checkers online do with hyperlinks must be done on TV with graphics. These must contain every number and source the fact-checker mentions — but nothing more. This often means losing a lot of contextual information compared to online fact checks.

While online fact checks tend to build up in a linear manner towards the adjudicated conclusion, TV producers seek opportunities for "infotainment." For some producers, this means prioritizing false claims because of a conception of television as driven by conflict.

That appears to be the case in some of the fact checks by Kallxo in Kosovo: a public figure's lies are exposed through a series of reported videos played back to the very author of the claim.

Alberto Puoti, of Italy's Rai 2, does not think conflict is the only way to capture audiences' attention. Puoti says you can obtain the "infotainment factor" any time a fact check reaches a conclusion that runs counter to widely held beliefs. The crucial thing for his is that the fact check deliver an element of surprise.

Explaining the salience of a statement in the political context tees up the fact check; once Spain's El Objetivo settles on a claim, it will look for instances when it has been repeated (as with this claim by Mariano Rajoy on China's pension system).

Having the host of the show present a fact check is not necessarily the most effective approach. A fact-checker engaging with the host on the content creates a more interesting dynamic for the viewer, says Alejandro Olvera of El Objetivo, whose host Ana Pastor initially presented the fact checks herself.

A strong host is undoubtedly helpful for fact-checking during debates — as this video from Kallxo shows — but can be counterproductive in other instances. "Presenters tend to come with a lot of baggage — if you don't like the individual, you won't trust what they are saying," says Worrall.

Once the transition from online to TV has been made, fact-checkers should make sure content also flows in the other direction. ABC Fact Check in Australia closes many of its fact checks with a call to action for viewers to find out more online.

Moreover, whatever clips are made for TV should have a second life on social media. This is a central part of Channel 4's strategy: All its videos are in an animated text-driven and square format that does best on Facebook.

This has meant that a recent Channel 4 fact check on the UK's budgetary contribution to the European Union is now approaching the 3 million views mark, an impressive feat (even if online video views are a flawed metric).