But, the audience measurement service has been trying to play catch up, building out what it calls its “total audience measurement” tool. This includes the recent launch of its digital content ratings metric that measures how many people consume a range of content—video, audio, and text—on desktop and mobile devices. Nielsen’s ratings system has always been critical to the TV industry, which depends on viewership statistics for its primary revenue stream: selling advertising. Now that modern television viewers’ habits have evolved, the research firm needs to adapt quickly to properly serve its TV industry clients.

Now, Nielsen is trying to add another small piece to the puzzle by tracking what consumers are watching on television even when they’re not at home.

The company said on Monday that it is launching a new out-of-home ratings service that will help national TV clients track the number of people watching something like a sporting event or a presidential debate anywhere from a bar or restaurant to a hotel, or even while working out at a gym. The announcement marks a big step for Nielsen as the company tries to present its clients with a well-rounded picture of how many people are watching a particular program, no matter where or how they’re watching.

Nielsen said the service, which will launch in April 2017 with data going back to January 2017, would use what the company calls portable people meters (PPMs) to track out-of-home viewing statistics. Nielsen’s PPMs are small, pager-like devices worn by participating consumers that can pick up on audio to track what, when, and where the person wearing is watching on TV. The company said last month that it now has more than 75,000 panelists using the PPM devices across 44 local TV markets in the U.S.

Two corporate clients that have already signed on with Nielsen are Disney’s ESPN and Time Warner’s Turner Broadcasting. ESPN said earlier this year that it was working with Nielsen to get an idea of how many people were watching the network’s live sporting events at bars, restaurants, gyms and other public spaces. The out-of-home ratings would conceivably increase the number of total viewers it tracks for sports programming on ESPN and other networks.

This particular effort comes at a time when ratings for live sporting events are taking a hit, with the Summer Olympics scoring below expectations this year and even the typically massively-popular NFL suffering a dip in ratings in recent months. Meanwhile, ESPN has seen its subscriber base drop by nearly 10 million people since 2013, as more and more people cut the cord on their cable packages.

In a statement on Monday, ESPN’s senior vice president of global research and analytics, Artie Bulgrin, called Nielsen’s new out-of-home measurement “a significant leap forward.”

“As a leading media company with a diverse portfolio of brands, Turner recognizes that today’s audience measurement requires constant innovation to capture the full scope of audience behavior,” Howard Shimmel, Turner’s chief research officer, said in his own statement. “For brands like CNN and Turner Sports, with huge and valuable out-of-home audiences, we need to be able to measure consumption regardless of the platform, screen or location.”

For instance, Nielsen reported last month that a record 84 million people watched the first presidential debate between Donald Trump and Hillary Clinton, including nearly 10 million who watched on CNN. But, those numbers did not include anyone who watched the historic event in large groups at a bar or other public places.

Out-of-home viewing is yet another step, along with better tracking of consumers’ digital and mobile viewing habits, toward Nielsen’s goal of providing its clients with the most modern, well-rounded viewership data possible. Nielsen plans to complete the full rollout of its total audience measurement tool by March of 2016.