The viewability guidelines endorsed by the Media Rating Council (MRC) are very similar to display in that half of the ad unit must be in view for it to be considered viewable, although in video 50% of the pixels have to be visible for two seconds rather than display's proviso of just one. It has to be said -- it's not the most exacting of standards to hit, yet still nearly half of all desktop video ads are not shown on screen, or even half shown on a screen, for two seconds or longer.
It's not entirely clear why this is. It is unlikely to be the result of people deciding to skip a pre-roll ad because, of course, the option doesn't appear until more than two seconds in to the ad being shown. So it sounds like a display issue where ad units showing video content are not properly in view or are scrolled away from within two seconds. It has been suggested that the issue could be partly the result of people opening another tab and looking at other content until a pre-roll is played and they can return to the video content. I think that is unlikely, as the technology would still consider the ad as served. The best bet is that just like display, video ads are simply not being served in spots where half of the content is physically viewable for two seconds or longer.
The big news that digital marketers should be coming away with is that mobile performs nearly twice as well as desktop, with more than eight in ten mobile video ads deemed viewable. The news that Google wanted people to come away with is that video ads stand a far better chance of being seen on YouTube, and the company produces figures to back the argument up, but overall the stunning result is that roughly less than a fifth of mobile video ads are unviewable compared to nearly half on desktop.
We could all come up with theories as to why mobile might be a better medium. The likelihood is that it's a device that holds our attention better and that people are often looking to be entertained on a smartphone, where it's not as easy to scroll around and navigate between multiple browser windows in the two seconds it takes for a video ad to be deemed as viewable.
Whatever the reason, it's a massive takeaway for digital marketers. It's been pretty obvious for a while that display advertising is going to struggle on mobile, because of small buttons and banners, and so the channel would appear to be far better suited to advertising that takes a more prominent role on the screen, such as video. Today's viewability figures lend considerable weight to the observation because not only is the medium suited to video, marketers can rest assured they are roughly twice as likely to have their creative rendered viewable on mobile compared to desktop.