EUROPE: The UK has the worst viewability rate in Europe for banner ads, according to a new report which suggests that the growth in mobile advertising expenditure is contributing to a continent-wide decline in ad viewability levels.

The latest quarterly benchmark report from ad verification company Meetrics indicated that just 47% of banners ads delivered in the UK met minimum viewability guidelines – 50% of the ad is in view for at least one second – during the first quarter of the year.

That was a two-point drop from the previous quarter and the lowest level for nine months. Based on recent IAB/PwC figures, this suggests that around £750m per year is being wasted on non-viewable ads.

The equivalent viewability figure for Germany was 55%, but that was down three points and an all-time low for that country, while Austria dipped one point to 67%.

Among the countries considered by Meetrics, only France bucked the downward trend, rising three points to 60%.

There are a number of factors affecting viewability levels, and Meetrics singled out one for particular mention.

"Declining viewability is partly driven by mobile now accounting for over half of display ad spend but tending to have lower viewability rates than desktop for various reasons," said Anant Joshi, Meetrics' commercial director UK & Ireland.

"Obviously, the smaller screen size can mean more page scrolling and, thus, more chance of ads being missed lower down a page, plus slower network connection speeds can cause ad loading delays.

"There's also the legacy issue of desktop ads served on mobile which don't format properly, despite the use of responsive design."

Joshi suggested that these issues are compounded by the increasing amount of mobile content consumed via apps, in which ads are more likely to be at the bottom of a page so don't always get enough attention.

"Unfortunately, we're still seeing a lot of talk but not the required intense effort to increase viewability and improve campaign ROI," he said. "This needs to change."

Data sourced from Meetrics; additional content by WARC staff