CHICAGO: There is an advertising industry consensus around the importance of viewability on digital and why it needs to become the basis for billing but there remain major hurdles to be overcome, a leading industry figure has said.

Speaking to, Vivek Shah, chair of the IAB and CEO of Ziff Davis, the media company, declared that "We're creating a standard within digital advertising that is different and better than other standards that exist in media – it's groundbreaking and it's unprecedented".

But there are challenges in a shift from billing on served ad impressions to billing on viewed ad impressions and Shah outlined four issues.

First he was concerned that publishers were being asked to make their systems compatible with too many viewability vendors. Fifteen of these had already been accredited by the Media Ratings Council and he said another 15 were in the pipeline.

He compared this situation with ad serving, where there were only two or three players in the marketplace and it had still taken 18 years "to bring discrepancies into a tolerable range".

Second, publishers already pay to serve ads and were then being told to pay a multiple of that to determine if they're viewable – "that doesn't make any sense" .

While he fully expected that this situation would change in due course, "right now you have a very cost-prohibitive viewability-vendor landscape".

Third, desktop was furthest down the viewability road, but even here "routinely 30%, 40% of inventory, for one reason or another, is deemed not measurable". That didn't necessarily mean it wasn't viewable, but simply that the vendor couldn't say definitely whether it had or hadn't been seen.

Fourth, there was a huge hole when it came to mobile, which isn't currently measured. "How can we send you a bill for viewable ads when 40% of the inventory is not even being measured?" he asked.

Despite these difficulties he remained an enthusiastic advocate of viewability and dismissed those publishers who complained about loss of inventory.

"We should lose inventory," he stated. "The inventory that has no opportunity to be seen needs to be pulled out of the supply chain – that's not a debatable element."

Data sourced from; additional content by Warc staff