What is viewability, and why it matters

Rhys Heron, Managing Director and Jonathan Devereux, Programmatic Manager at Mi9 share their insight and expertise on the subject of viewability.

Imagine that you’re driving down a busy motorway and spot a billboard advertisement facing the other direction. As a marketer, you think: “Why would the advertiser do that, everyone knows you will get more views facing it the other way”. 

Spotting this in a real-world situation may be easy, however when it comes to digital ads, it’s a little more tricky.

As a marketer working in the digital advertising sphere you might have heard about viewability.However, the speed at which technology is advancing many still have confusion about what viewability is, what the standards are and why it matters for digital advertisers.

Simply, viewability is a metric in digital advertising speak that tracks ad impressions which are actually seen by real humans. These impressions are called ‘viewed impressions’, and are not to be confused with impressions on a computer or mobile screen from the likes of blog and social postings.

Rhys Heron

What is viewability – a definition

At a more technical level, a viewable ad is regarded as an ad that a user has an “opportunity to see”. The technical definition of viewability is maintained by the US-based Media Rating Council (MRC) and there are definitions for both display and video advertising:

  • The definition of viewability for display advertising requires that 50 percent or more of the pixels in the advertisement were on an in-focus browser tab on the viewable space of the browser page and that this condition was met for one or more continuous seconds, post rendering of the ad.
  • The definition of viewability for video advertising also requires that 50 percent or more of the pixels in the advertisement were on an in-focus browser tab in the viewable space of the browser but the video advertisement is played for two continuous seconds. It is not necessarily the first two seconds of the ad that need to be played, but any unduplicated content comprising at least two continuous seconds is enough for the definition to be met.

There are two caveats to this definition worth noting:

  • If the measurer can determine there is a strong user interaction with the ad, then the ad may be counted as viewable even if it does not meet the pixel and time criteria above. In this context, a legitimate click (one that satisfies the separate definition required for counting a click) would constitute a “strong user interaction” that would result in a viewable impression.
  • For display ads of 970×250 pixels or greater, a viewable impression should be counted if 30 percent of the pixels in the ad are on an in-focus browser tab on the viewable space of the browser page for a minimum of one continuous second.

Leaving these caveats aside, to summarise the standard definition of viewability and why it provides the user with an “opportunity to see” an ad: 50 percent or more of the pixels of the ad must be viewable on the screen in the active browser and; a display ad must be viewable for at least one continuous second and a video ad for at least two continuous seconds. This represents an “opportunity to see” the ad because, even if the user didn’t notice the ad, there should have been enough of the ad visible, for long enough, for them to notice it if they wished to.

Why does viewability matter?

Viewability is an important concept in digital advertising because it provides a minimum threshold for the amount of an ad that should be visible, and for how long, for it to be considered possible for the user of the browser to have noticed it and understood something about it. It is a minimum standard as the impact an ad can have meeting this threshold is likely to be low and can only improve if more of the ad is visible and for longer.

However, the standard at least excludes ads that never had the opportunity to be seen by the user, such as those that render in an inactive browser tab, or below the fold of the active browser tab, for example. Ads rendering in those scenarios may count as impressions, but not viewable impressions.

Viewability gives the buyer of digital display and video advertising a yardstick by which to measure and understand how many of the impressions bought during a campaign at least had some potential to influence the user. An ad that does not meet the viewability threshold can be assumed to have little or no potential to influence the user towards a campaign’s objectives. 

It’s important to note that viewability should not be an objective of a campaign itself. Every digital campaign should have a defined objective like brand awareness or conversion to a transaction, such as a purchase or test drive booking, for example. More viewable impressions should lead to better performance towards a campaign’s objective but do not guarantee that it will. 

However, when reviewing the economics of viewability, if a buyer is paying 100 percent more per one thousand ad impressions for inventory that is 50 percent more viewable, it can be a less than optimal scenario. A better approach may be to work out a cost per 1000 viewable impressions (CPM), e.g. CPM / Viewability Rate. In this way a publisher with a viewability rate of 50 percent may offer better value, assuming the average CPM on their site is low enough:

CPMViewability RateViewable CPM (vCPM)

In the above example, the less viewable advertising inventory, at 50% viewability, proves more economical when starting CPM and viewability rate are both factored in.

How is the market approaching viewability today?

Over the past few years supply-side platforms (SSPs), demand-side platforms (DSPs) and third-party tools such as IAS and DoubleVerify have become more sophisticated in their measuring capabilities. This has resulted in increased focus from both buyers and sellers on the reported viewability of ads, with buyers wanting to maximise the viewability of their ads to present the best possible opportunity for a conversion to happen, and sellers wanting to maximise the quality of their inventory using tactics, such as refreshing highly viewable ad slots, sticky banners and lowering site latency, to maximise the times ads are in view. Overall, this has led to a significant increase in the viewability of ads across the Internet.

When viewability was the buzzword of the day buyers may have gone overboard with their focus on viewability, to the point of hurting the performance of their campaigns. Overlaying strict brand safety rules on top of high viewability thresholds will limit the inventory available to buy, possibly to the point of jeopardising the reach of a campaign, as well as its ability to deliver, which may result in needing to loosen frequency caps or raise CPMs, both likely detrimental to the performance of the campaign.

If viewability is important, how can I address it in my campaigns?

If, after reading this, you agree viewability is important, the first thing to do is measure it. Using tools at your disposal, or working with your media agency, understand the viewability of the display and video advertising you’re booking for your campaigns. Then develop a target threshold for viewability for the campaigns you book, in addition to other criteria relevant to your campaign objectives. For example, Outlook.com offers exceptionally high average viewability of 92 percent.

As open market programmatic buys rarely work on a placement level, many publishers are included or excluded from buys based on the aggregate average viewability of their domain. An alternative solution might be to reach out to publishers and build specific private marketplace (PMP) deals including or excluding specific placements to find fair value at a more granular level.

A benefit to publishers selling their lower quality inventory at a lower agreed rate, is the remaining high-quality inventory facing the open market would lift the quality of the site for open market buyers and algorithms. Likewise, a benefit to agencies would be a more granular and cost-effective solution to source inventory at scale, at comparable rates. In this sense, granularity helps both parties find fair value for their inventory.

At Mi9, one of the benefits of having boots on the ground and maintaining relationships with local agencies is being able to responsively build custom deals. We encourage buyers to reach out and work with us to build segments to achieve desired goals, at rates that benefit both parties, using the viewability and audience data available, to make better use of our inventory and hopefully provide better value for buyers in-market.

In association with Mi9.

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