Viewability is not the solution to all of your problems

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Viewability has been hailed as the next great ad performance metric. It allows advertisers to determine if their ad was actually seen, and therefore confirm the performance of their display ad campaigns.

In this way viewability has become a byword for ad quality, and a way to determine if campaigns are performing as expected.

Viewability can be important for a few reasons:

  • It is a way for advertisers to gauge the quality of the impressions that they are paying for
  • For both direct response and branding, ads need to be viewable - why pay when they're not?
  • If different advertising opportunities are being compared (sites, placements, networks),  preferential treatment from advertisers may be shown to those with higher viewability.
  • Facebook is already leading with 100% viewability guarantees

The advertiser/publisher relationships could play out in the following way: advertisers demand 100% viewability, and so the volume of qualifying impressions decreases. Once the impressions volumes decrease, the publishers will demand higher CPMs in order to retain revenue.

Viewability as a metric is new and difficult to compare to the usual cost per thousand (CPM) and click-through rate (referred to as CTR) metrics that the digital ad industry has been working with for years now. The industry hasn't even decided if 100% viewable is better than 50% yet. In fact, some digital marketing agencies are seeing viewability metrics of as low as 60% returning the most benefit for a given campaign. It's also another metric to be gamed with modern bots focusing on emulating highly viewable impressions.

Since this metric is being pitched by and for advertisers as the best way to track display campaigns, improving viewability, and its related key performance indicators, can be a way for publishers to keep advertisers satisfied moving forward. On the other hand, both advertisers and publishers may decide that viewability it is not something that is important to the success of ad campaigns. It's completely possible that it's irrelevant for direct response, as the CPMs will correspond to campaign KPIs anyways.

One large issue that remains for the adoption of viewability is the standardization of its measurement. There are only a few vendors capable of measuring viewability, and the numbers reported by different vendors vary, due to their differences in measurement techniques. Google has called for a standardization of the metric, citing the need to be able to measure things without discrepancy. Publishers making changes to optimize viewability could very well be wasting their resources as the metric changes through development.

While there is a delta in measurements by various vendors (Moat, IAS, Google, etc.), each vendor touts how much better theirs is for advertisers. While standardization would be ideal for publishers, it's actually bad for vendors because it brings commoditization and reduced pricing power, so they're motivated to be differentiated enough to end up being the defacto currency for ad spend. However, given the efforts by the Chrome team to standardize the technical implementations (thankfully, as this improves things for users), and the MRC (Media Ratings Council) to validate them, most implementations will converge and commodify over time.

But we're not there yet. Currently both vendor differences and timing differences (e.g. tag on page, nested) with pixel firing cause enough discrepancy to leave most constituents suspicious and dissatisfied. Because of this we thought we'd look at click-through rate as a proxy metric for viewability.

The difference between viewability and click-through rate is the interaction required. The measurement of viewability doesn't need a discrete input (a click, in the case of click-through rate) to be recorded in order for the viewability interaction (the length of time that the ad is visible on screen, in the case of viewability) to be measured.

Using click-through rate to determine performance does have a couple of advantages over the proposed viewability standard though. It is simple to measure, understand, and compare across platforms and ad types. On the other hand, it is not very useful for measuring exposure, brand awareness, or other types of purely display-driven metrics that many campaigns are designed for.

Why would we want to relate click-through rate to viewability? Because by definition, anything that has been clicked was viewed, and therefore viewable. It's pretty difficult to click something that isn't viewable (unless you are a bot, but that's another article). The viewability metric is offered as a way to track display ads and determine if they are indeed being seen. What better way to learn whether or not you are offering viewable ad inventory than looking at where ads have been clicked in the past?

While we know that display ads are designed differently than click-through campaign ads, the concept behind this exercise should still hold true: an ad that has been clicked was viewable. In terms of general trends, as click-through rate decreases, viewability also decreases. Maybe comparing click-through rate to viewability isn't so crazy after all. Maybe looking at click-through rate can provide some real insight into viewability.

CTR and viewability with trend lines

Click-through rate versus Viewability

Using our click-through rate data as proxy, we can map the areas of highest potential viewability and try to figure out what this data might mean for the future of ad tech around the viewability metric.

One of the first things we notice is that click-through rate is spread surprisingly evenly down the page. It does not carry the same above the fold bias that most pages with ads carry. Since this is the case, why have impressions not been spread down the page as well? If the use of click-through rate has not changed impression density, is viewability supposed to spark that change?

In the same way that display advertising is a much larger and more significant market than click-through advertising, will viewability become a small and insignificant metric in time? Will the industry decide that viewability is just not important for ad campaigns?

Viewability is a very beneficial metric for advertisers, as it allows them to confirm if their ads are being seen to the degree that they are hoping. The benefits for publishers are not as clear. If the incentives for using a metric are clearly one-sided, can we expect the metric to succeed and become a standard? Apart from advertising pressure, is there any reason for publishers to measure viewability across their web sites?

Finally, does the use of viewability result in a more profitable or sustainable digital advertising ecosystem? The success and adoption of viewability will most likely be due to whether it can positively impact the industry.

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