Viewability in Digital Advertising

The online advertising industry has been focused for more than two years on the study of and debate over online ad viewability.

What is viewability? A banner ad could be considered ‘viewable’ when 50% or more of it is visible for one second or more, or 50% or more for two seconds, on a video ad. This matters because it is how media sources are measuring how many people are viewing your ad, but the impact of a message in such a short amount of time is debatable.

The debate centers on whether an advertiser should pay for impressions that are not deemed viewable by a third-party verification source. Another factor in the debate is that an ad may be viewed by a user, but it still registers as non-viewable because verification technology cannot fully measure all websites. The percentage of ads deemed viewable by industry experts can vary.



The American Association of Advertising Agencies (4As) said in December 2014 that it will “not endorse” the online advertising guidelines put forth by the Interactive Advertising Bureau (IAB), which suggests the online ad industry should aim to have their campaigns achieve a “70% viewability threshold” in 2015 (meaning 70% of the ads meet the viewability standard). The IAB also said 100% viewability measurement is “not yet possible” due to the myriad of ad units, vendors and measurement methodologies. If a campaign does not meet that threshold, additional ads should be given to the advertisers to make up for the shortfall, the IAB said. The 4As, however, doesn’t feel the bonus ads are adequate, and an advertiser should simply have the option to pay only for the ads that were measured as viewable.

An online ad’s ability to actually be seen can be hindered by a number of factors: actions taken before the ad loads and renders; multi-tasking (browser is minimized or switched); low-quality or compromised site pages; ad loads in an area out of the user’s browser window; frequent page refreshing prevents ad from loading; and web load errors.

As advertisers, we are concerned about these external factors that can alter the effectiveness of paid advertising, rendering the money spent fruitless. There are additional and more devious ways that an ad can be marked as viewable by a third-party source (considered ad fraud). These include pixel stuffing (stuffing an entire ad-supported site into a 1×1 pixel); ad stacking by placing multiple ads on top of one another in a single ad placement with only the top ad in view; and illegal bot traffic, compromised computers with breached security defenses conceded to a third party.

So what can we learn from this debate?

We know that our Media Buyers must remain diligent about the transparency and quality of the digital media they buy. Some best practices that we use and encourage include:

  • Choose partners that will only charge for viewed ads
  • Be transparent with your third-party verification (and use a partner accredited by the Media Ratings Council)
  • Be clear on your delivery expectations regarding in-view, geography, frequency and non-human traffic (NHT)
  • Base your currency on audience impressions – viewable – rather than gross impressions served
  • When buying programmatic or real-time bidding (RTB), remain conscious of your relative costs, versus viewable impressions served
  • Know the technology and its limitations

Years ago, discussion of ad efficacy was often tied to TV or Print media channels. We’ve always known that a viewer or subscriber may glance past an ad leaving it unseen, and gaps in measurement have been understood and accepted. Now, it’s digital ad viewability’s turn in the hot seat. We’re pleased to see so many public forums carry this conversation; only with a collective rise in our knowledge will we see more solutions to the factors affecting viewability.


Jon Bross

- Author -

Jon Bross

Media Director