Ad Viewability Definition and How to Approach Viewable Ads

Passendo’s guide breaks down what ad viewability means, how to measure it and provides tips on how to approach and improve viewable ad impressions.
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Ad viewability is a relatively new concept in the advertising industry. It is one of the core aspects of the evolving marketing industry that must continually find new ways to monitor and understand how their ad campaigns are viewed and received by their intended audiences.

This article offers an in-depth insight into the concept of ad viewability. Some of the topics covered include the importance of ad viewability, how to measure viewability, and how advertisers and publishers should approach ad viewability for greater success. 

What is Ad Viewability? 

Advertisers traditionally based their metrics for ad campaigns on the number of ads served. Ad viewability is a concept that refers to how much of an ad is visible and for how long. Advertisers and publishers have adopted it to overcome the inefficiencies of number-based ad campaign metrics, which don’t necessarily reflect the actual number of views. 

What is the IAB Standard for Ad Viewability? 

The Internet Advertising Bureau (IAB) sets two standards for ad viewability: 

  • At least 50 percent of a display ad should be visible for at least one second. 
  • At least 50 percent of a video ad should be visible for at least two seconds. 

The Media Ratings Council (MRC) also has a range of guidelines used as a standard for measuring viewable impressions. It is worth noting that these standards are dynamic, and they change as the industry seeks a more definitive ad performance metric. 

What are Viewable Impressions? 

A viewable impression is a metric by which advertisers measure the number (or percentage) of ads seen by human users. It is the ad viewability concept’s standard of measurement according to the IAB, as explained above. 

How to Measure Ad Viewability 

Ad viewability is measured according to the standards set by the IAB and MRC. Advertisers and publishers use a range of tools to measure viewability, including Google’s Active View solution. 

Ad viewability measurement is based on two aspects: time and size. To this end, at least 50 percent (size) of a display ad must be visible for at least one second (time). The IAB lowers the size requirement for big ads (ads measuring more than 242,000 pixels) to 30 percent. For video ads, at least 50 percent of the video’s display area must be visible for at least two seconds as the video plays. 

Google offers it’s Active View solution with all of its advertising products. This tool measures viewability in real-time based on the standards and guidelines set by the MRC and IAB. The tool locates and measures the portion of an ad creative displayed in the ad’s frame using a DIV algorithm inserted during rendering.


Why is Ad Viewability Important? 

In 2014, Google reported that more than 50 percent of all rendered ads didn’t reach users. Back then, the number of ads served was the standard metric of measuring campaigns. This changed when the industry realised that previous ad viewability reports were overstated by about 50 percent. 

Ad viewability is an important metric because it improves accuracy when measuring a campaign’s performance. It enables marketers to do the following: 

  • Ensure Cost Efficiency 

Marketers realised that they were paying twice the value of their ads following Google’s explosive 2014 report. More than half of their ads were not viewed by users, but they still paid publishers for the whole inventory. 

Ad viewability enables marketers to pay only for the ads that have actually been seen. Essentially, they pay less for more value, ensuring that they get their money’s worth. 

  • Gauge Ads’ Quality 

Google’s 2014 report indicated that users didn’t care much for ads, explaining why more than 50 percent of all ads went unseen. This was also indicative of these ads’ poor quality based on users’ standards. Naturally, users will be interested in seeing interesting and engaging ads. 

More marketers now use viewability as a metric for measuring ads’ quality. Interestingly, the percentage of ads seen rose to 65 percent in 2019 following the adoption of the ad viewability concept. 

  • Gauge Quality of Publisher’s Inventory 

More advertisers now demand 100 percent viewability from their publishers since Google’s 2014 report revealed that more than 50 percent of publishers’ inventory was not sellable. Consequently, advertisers are buying less inventory than they did before.  

Viewability is an important metric for measuring the quality of publishers’ inventory. Marketers use this metric to identify the best publishers, while publishers use it to improve their inventory’s quality. 

What Affects Ad Viewability? 

Several factors affect ad viewability either positively or negatively. Some of these factors include: 

  • Number of Publishers  

Google’s 2014 report concluded that users did not see 56 percent of display ads. However, other studies found that the average publisher reported an average viewability rate of 50 percent. The difference of 6 percent is caused by the high number of publishers in the industry. However, this does not diminish the impact of Google’s report — or the importance of ad viewability. 

It is also worth noting that some publishers deliver a higher viewability rate than others. For example, Facebook guarantees a 100 percent viewability rate for all display ads. 

  • Page Position 

Many marketers presume that the top of the page is the best position to place an ad. However, studies revealed that the top of the fold is a better position. This position is especially recommendable for ads measuring 300 × 250, 728 × 90, and 320 × 50.

Ads positioned above the fold enjoy a 68 percent viewability rate — the 32 percent lack of viewability is attributed to users scrolling fast — faster than the one-second standard — down the page. In contrast, ads positioned below the fold register a 40 percent viewability rate. 

  • Ad Size 

The ad’s size also affects its viewability as it is one of the metrics used to measure ads’ performance. As mentioned, at least 50 percent of an ad must be visible for at least one-second for the impression to be considered viewable. Consequently, larger ads are more viewable because they stay on the screen longer as the user scrolls down. 

Thus, ads measuring 120 × 240 enjoy the highest viewability rate averaging at 55 percent. The common 300 × 250 ads are smaller and get an average viewability rate of 41 percent. 

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