AUSTIN, TX: More than 5bn rich media ad impressions on mobile devices were wasted in the first quarter of 2015 alone, according to a new report which has found advertisers continuing to run Flash-based ads even though this format isn't widely supported.

The Sizmek Mobile Index was based on data collected from ads served via the Sizmek MDX Platform, which represents marketing activity for more than 3,400 agencies, 17,000 brand advertisers, and 22,000 global web publishers in more than 70 countries.

The report said that while mobile ads tend to get more clicks than desktop, the interaction rate (i.e. the total number of interactions out of the total number of served impressions) for desktop ads was nearly five times higher than for mobile.

It attributed this primarily to Flash mobile ads defaulting to static ads, where a click is the sole opportunity for interaction.

"Advertisers are using more rich media on mobile to reach potential customers, but they're wasting a lot of opportunities," said Andy Kahl, director/research at Sizmek.

"By converting rich media ads to HTML5," he advised, "brand advertisers can ensure that their ads are seen as intended, thus increasing return on their ad spend."

Sizmek's analysis indicated that HTML5 ads outperformed Flash ads by 400% in terms of interaction rate.

And while rich media ads relying on Flash defaulted 98.6% of the time, those in the HTML5 format only defaulted at a rate of 8.3%.

Further, one in eight advertisers had never served a successful rich media ad to a mobile device.

"Left unchecked, at least 33bn Flash impressions will default in 2016, resulting in the loss of nearly 400m interactions," the report calculated.

But it added that it was unlikely that mobile advertisers would ignore this level of wastage and expected they would adopt HTML5 as standard while developing new ways to reach mobile users.

The report did not only look at the cost of format failure. It also found that mobile's share – smartphone and tablet – of display impressions had nearly doubled year-over-year, from 15% to 28%.

Data sourced from Sizmek; additional content by Warc staff