Nielsen is to start measuring the performance of ads served to users of YouTube's mobile app in the UK, France and Germany.
The move will expand YouTube's subscription to the measurement firm's Digital Ad Ratings service beyond its mobile and desktop browser services, giving marketers access to cross-device insights.
Nielsen Digital Ad Ratings clients will have access to age and gender demographics for consumers viewing ads on the YouTube mobile app as well as reach, frequency and gross rating points (GRPs).
The deepening of YouTube's relationship with Nielsen follows on from the director general of the Institute Practitioners in Advertising (IPA), Paul Bainsfair, last year urging both Google and Facebook to take "urgent" action in addressing issues around measurement, brand safety and viewability.
YouTube already has existing deals with Nielsen around its apps in countries like the US, Canada and Japan, with further expansion into international markets planned.
“As more people watch video across digital platforms and devices, Nielsen’s comprehensive measurement of YouTube through Digital Ad Ratings is crucial to provide a complete picture of media consumption, especially since YouTube accounts for a large share of mobile video advertising in the UK.” said Barney Farmer, Nielsen's UK commercial director.
“We are proud to be able to provide the market with an independent view of the audience for advertising on YouTube in context of the wider viewing landscape.”
In September 2017, YouTube updated how it works with partners like Oracle and Nielsen in the US, announcing a deeper integration to allow marketers to measure the offline sales impact of YouTube campaigns.