BARCELONA — With data suggesting a large percentage of online ad views are being called by fake users (malicious lines of code written by nefarious publishers racking up fraudulent clicks), advertisers have become worried.

Now the boss of the world’s biggest ad agency holding group is repeating his call for online platforms to do more for his customers.

“Our second largest client, Keith Weed, CMO of Unilever, has already sounded off about the three Vs – value, validation and viewability,” WPP CEO Sir Martin Sorrell tells Beet.TV in this video interview from Mobile World Congress.

“Viewability on Google and Facebook is critically important. Some of those frenemies are being helpful, some are not. We are going to have to up the tempo in terms of making sure that the data is right and consistent and properly measurable.”

The ad fraud problem is prompting responses ranging from detection software and a move from display to native ads, to a demand from advertisers who only want to pay for ads that are viewed by human users.

But WPP companies are doing their bit in the new world of advertising. The company runs data-driven ad tech outfit Xaxis; Light Reaction, a vendor putting the performance in to programmatic, as well as a host of other properties and investments.

In what has been a year of challenge for agencies – tasked with proving their worth in the new world to clients, many of whose contracts have come up for renewal – Sorrell says WPP has fared well.

“We’ve been the biggest net winner, we’re +$1.5bn,” he claims, citing latest RECMA media agencies benchmark data describing new business wins.

“There’s been big $5bn swing between the strongest and the weakest. That demonstrates the importance of technology.”

This video was is part of Beet.TV’s coverage of Mobile World Congress presented by Light Reaction.   Please visit this page for additional videos from Barcelona.