Media-measurement firm comScore is now providing YouTube mobile viewing metrics to partner channels of the Google-owned video platform — promising a far more complete picture of their audience.

Mobile measurement has been included in comScore’s Video Metrix reports since September 2015. Now, content owners who have YouTube partner channels have access to channel-level insights across the video ecosystem that includes both desktop and mobile-based consumption.

An estimated 70% of YouTube video views are on smartphones or tablets, so comScore’s desktop-only reporting for YouTube channels hasn’t reflected the majority of the viewership on the platform. In fact, in examining December 2016 U.S. data for the 50 biggest YouTube channels, comScore found that on average each channel expanded its desktop audience reach more than threefold — by 218% — after including consumption on smartphones and tablets.

In addition, total viewing time on the top 50 YouTube channels increased a whopping 380% over desktop-only measurement when accounting for mobile viewing. And comScore said 69 YouTube channels reached a monthly audience of at least 10 million viewers across desktop and mobile combined for December 2016, compared with just 15 channels that hit that threshold on desktop alone.

“We’re happy to continue to partner with comScore to ensure that YouTube is included in their digital reports,” a YouTube rep said in a statement.

YouTube works with other third-party measurement partners, including Nielsen, which measures YouTube viewership per content partner (across desktop and mobile) in its Digital Content Ratings product that launched in September 2016. In addition, YouTube says it integrates with hundreds of other third parties ranging from ad-tech vendors to data providers. Last year YouTube started enabling third-party viewability measurement, and Google this week said the YouTube viewability reporting partnerships with Moat, Integral Ad Science and DoubleVerify will undergo a “stringent, independent audit” for Media Rating Council accreditation.

Industry execs applauded comScore’s move. “These improvements to YouTube’s video coverage in comScore help further validate audience viewing on mobile, emerging as consumers’ primary screen,” said Pete Stein, GM at Fullscreen, the digital network owned by AT&T and Chernin Group’s Otter Media. “Accounting for the huge share of viewing on mobile advances major measurement gaps.”

For the majority of Vevo’s users, “mobile devices are the first and only screens” they use, according to Roberto Santos, director of audience research at the music-video service. “This fact makes it essential that we have access to granular, cross-screen insights about how Vevo content is being consumed across various channels,” he said.

ComScore said mobile video viewing data for YouTube — which includes viewing on both apps and mobile web — is now integrated into Video Metrix for syndicated digital video measurement.

As for when comScore plans to add connected-TV viewing to its reporting, VP of product management Naresh Rekhi declined to share specific timelines but said the company is continuing to work on offering comprehensive cross-platform measurement. Currently, the firm reports on connected-TV and over-the-top-based consumption for several content creators and distributors within its video products including Video Metrix.