What Is Viewability?

Viewability has been one of the more contentious issues in digital advertising for several years, in spite of the fact that MS Word apparently doesn’t recognize it as a properly spelled word. That’s appropriate, in a way. Media types have found the viewability issue maddening, and most laypersons would never really need to think about it.

Let’s take it back to the late ‘00s. There was a time when study after study showed that despite ever-increasing brand spending on digital ad inventory, massive percentages of the impressions they were buying were never seen by an actual person. We’re talking about ads loading at the bottom of the page, ads in slots partly obscured by page content, ads on a page the user bounced off of almost immediately, ads that are seen only by bots, and so on. Advertiser brands got all up in arms over this perception that they were wasting loads of money. In a way, it’s hard to blame them—they’re paying to reach their consumers, and they want a chance to do that. In another way, the counterarguments also make sense—advertisers have bought non-viewable inventory throughout the entire history of print, and just maybe the cost of non-viewable inventory was already a consideration in setting CPMs.

Various vendors came along with solutions for measuring viewable impressions and optimizing campaigns for viewability. The problem was, the industry hadn’t come together on a standard for what makes an ad “viewable.” In 2011, advisory groups the IAB, the ANA and the 4As together launched an initiative called Making Measurement Make Sense (3MS), with the goal of standardizing ad campaign measurement metrics and methodologies. Their first order of business was to create some kind of consensus around viewability.

The Media Rating Council joined in to come up with a workable industry standard for viewability. They came up with, for display ads, 50% of pixels in view for at least one second; and for video, 50% of pixels in view for at least two seconds. Other standards have been taken into account since—for example, a large-format ad is viewable if 30% of pixels are in view for one continuous second. In 2016, the MRC announced mobile viewability guidelines consistent with desktop for both display and video—while also recognizing “sub-second” impressions (imagine impressions viewed in a scrolling environment), which it counts as non-viewable.

One of the goals in the viewability discussion has always been transacting on viewable impressions, as opposed to the old method of transacting on impressions served. That’s been tricky. The MRC initially discouraged transacting on viewability, claiming the industry wasn’t there yet, and it didn’t green-light transacting on viewability until 2014. On the other hand, in 2015, GroupM famously announced it would count and pay for impressions only when they were 100% in view for display, or 100% in view and played 50% of the way through with the audio on for video.

Pushback from publishers and trade groups typically cites a few problems with rigid, high viewability demands: There are a lot of discrepancies among vendors in how viewability is measured, and custom or native ad units can be hard to measure. Different entities across the supply chain might interpret the standards differently. In 2015, the IAB, with guidance from the MRC, stated that viewability couldn’t be measured 100% of the time, recommending a 70% viewability threshold for measured impressions. In other words, it assumes a percentage of served impressions will not be measurable using current methods.


AdMonsters resources:

The Places Viewability Can Go: Dynamic Ad Serving and Selling on Engagement (2017)

Ad Ops Decoder: What Is the Intersection Observer? (2017)

How GroupM Executes 100% Viewable PMPs (2017)

Begin Pondering “Begin-to-Render Impression Counting (2017)

Inching Toward Mobile Viewability (2016)

The Engagement Light at the End of the Viewability Tunnel (2016)

The Obstacles to 100% Viewability (2015)