Visitors want fast websites, but advertisers want brand safety and viewable ads. In the end, ad concerns often end up winning at the expense of the user experience.

According to data ad tech consultancy RedBud — examined for Digiday across 15 of the top 20 U.K. publishers — brand safety, viewability and verification tags represent on average 10 percent of the total weight of a website. In some individual cases that number was closer to 21 percent. The company calculated the weight in kilobytes by measuring weight of ads, editorial content, tracking pixels and cookie-synching redirects.

Naturally, there is a knock-on effect to page latency, therefore user experience. Two publishers interviewed for this article said that viewability, brand safety and verification tags were causing up to six seconds page latency on desktop.

However, RedBud has calculated the average page lag caused by brand safety, viewability, and verification tags to be closer to 1 second per page view, per publisher. “There can be other factors such as internet speed and performance of the vendors’ servers, as well as how complex the publisher website is,” said Chloe Grutchfield, co-founder of RedBud. “For example, if you have loads of tags competing you will get slow responses.”

Nevertheless, it’s enough to make a noticeable difference, she added. One publisher executive who wished to remain anonymous said that there are five ad slots per page, and those five ads make an average 70 calls per page view, at around 200 to 300 milliseconds per call. Three vendors are making these blocking and tracking calls. Integral Ad Science has been highlighted as the heaviest of the viewability vendors, making between nine and 11 calls per single ad request, according to the same publisher.

Integral Ad Science’s verification code is 48 kilobytes, which is roughly equivalent to the standard display banner weight set by the industry ten years ago, according to the company. “Given the speed of today’s devices and internet connections, we believe any impact to latency is minimal and far outweighed by the need for transparency in the digital advertising ecosystem, which provides benefits to publishers as well as advertisers,” said a spokesperson for Integral Ad Science.

However, five publishers spoken to for this article want it addressed.

Publisher hand-wringing over meeting viewability expectations is nothing new. Whether it’s the pressure to over serve impressions in order to hit viewability targets set by agencies, or deal with the knock-on effect to page latency. But many believe the issue has magnified more recently as agencies have increased more of their own brand safety, viewability and verification tags around ads.

“It has become more of an issue as there are more [viewability and brand safety] vendors now,” said an executive at a national publisher. “We used to just use one verification vendor, but now advertisers all want to use their own tech on top of what we use, because brand safety and viewability have been bigger issues. So with the agencies and advertisers doing more their end that leads to more calls, a duplication of efforts.”

An agency will often supply ad creatives with viewability and brand safety tags, which are then added to the publisher’s own tools — often the same vendors. “It’s like wrapping the ads in two blankets,” added the same publisher. “It comes down to lack of trust.”

One of the unintended consequences of viewability tags being used by both publishers and agencies, is that there remain large discrepancies between what either side sees — up to 15 percent according to RedBud. Publishers are often faced with agencies refusing to pay for certain impressions because their own data shows that the ad hadn’t loaded in time to be in view. “It’s often the actual buy-side ad loads which impact viewability, which we then get penalized for,” said an executive at a digital publisher.

Four publishers cited that they’re having issues with their current viewability and verification providers, which are dominating a lot of weight on the page, therefore processing time. The issue is amplified on mobile, according to the same executives.

“There is a fundamental problem we have got ourselves into as an industry,” said an executive at a magazine publisher. “Due to lack of trust publishers are having to deploy technology to validate and prove what’s happening on the buy side. So you have verification providers making constant calls back and forth to the ad server, due to the complex nature of how they capture data.”

Publishers are searching for pragmatic answers. “It’s bubbled up again as an issue in the last three months. We need to look at how we can improve it. If we’re all using the same tags, so are there better things we can do, like have them cached or saved every time, a bit more like how Google Amp works. Then if one publisher uses a specific vendor, the code has been saved and doesn’t have to be reloaded every time,” said the same publishing executive.

Others have started scrutinizing viewability discrepancies more closely. “We are looking at our own validation tools for all campaigns prior to activation,” said an executive from a different magazine group. “This allows us to identify any issues with the tags early on. Additionally, we will be working closely with our agency partners to understand the implications of viewability discrepancies and identify firstly, the range of discrepancies and, secondly, any consistencies that may exist.”

Source of chart: Google Page Load speed tool
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