Instead of going to the bathroom or grabbing a beer during commercial breaks, TV watchers are increasingly turning to a new ritual: checking their phones until the show resumes.

For advertisers paying top dollar for TV ads, the trend is frustrating, presenting yet another challenge in their quest to gain a share of consumers' fragmented attention.

But Xaxis, the WPP-owned programmatic platform, believes it's found a way to reach these distracted consumers. The company is introducing a product called "Sync," which will give advertisers the ability to serve ads on TV watchers' mobile devices while their TV screens air the corresponding commercials.

"One of the biggest challenges that advertisers have right now, especially when it comes to buying broadcast television, is that up to 50% of people that are watching broadcast television are also engaging with another device," said Xaxis CEO Brian Lesser in an interview with Ad Age. "What we're trying to do with Sync is to solve the problem of users being distracted by their mobile device from the TV."

Sync takes an educated guess as to which households are watching the TV show its clients' commercials are running on. To figure this out, it combines TV watching behavioral data from Kantar Media with geographic data and other signals, including whether a consumer's device is logged into a home wifi network and stationary.

When Sync thinks a person is likely watching a show, it will serve ads targeted to their mobile devices as its client's TV commercial airs. Sync connects to satellite data, getting a two-second heads-up on which commercials will run as the TV show goes to break. When a client's ad is set to play, Sync will turn on its ad campaign and keep it live for a few minutes.

Xaxis will run the ads across its own inventory pool, Facebook's FBX exchange and, at times, through other ad exchanges.

The science is inexact, as Xaxis can't know for sure whether the audience it is reaching is definitely tuning in. But the company said a version of Sync is live in the Netherlands and generating improved click-through rates. The Sync ads will cost $5 to $10 dollars per thousand, according to a Xaxis spokesman.

More than just covering all the bases
Xaxis hopes Sync reinforces TV ads as well. "It's not only preventing the user from being distracted by the TV," Mr. Lesser said. "It's actually reinforcing the television commercial. Yes they're distracted but they are registering what's happening on the TV, and that just pays off,"

One way advertisers can put this into practice is by running a call to action on mobile while the TV commercial airs. "Unfortunately, you can't click through a television commercial," said Xaxis Director of Product Development Mike Finnegan. "If you have an ad for a restaurant -- where's the nearest one? How do you provide a store locator function? Give them something to redeem, or at least dive deeper on it."

And of course, the technology doesn't have to be used only when a brand runs its own ads. "Think of auto," Mr. Lesser said. "If there's one luxury brand that's showing on your TV, we can now buy in real time what you're looking at on your mobile for their competitor."