What is ad viewability and how it works?

Viewability is an important term in the digital advertising industry. Viewability has the potential to change how the digital advertising works out. In this post, we will explain what viewability is and why is it important, how it works and most importantly, what causes ads to be not ‘viewable’.

Table of content

• What is Ad Viewability?
• What are viewable impressions?
• How to calculate ad viewability
• What causes ads to be not ‘viewable’?
• Why is Viewability Important?

What is Ad Viewability?

Ad viewability is a metric used in digital advertising to measure how visible the ads are to users on the website.

According to the Interactive Advertising Bureau’s (IAB) and Media Rating Council (MRC) standard, for an ad to count as viewed, 50% of the ad must be visible to a user for at least 1 second. For video ads, 50% of the ad must be visible for at least 2 seconds.

What are viewable impressions?

Every time an advertisement shows up on a laptop or mobile device, it is known as an impression. These are classified into three types:

Eligible impressions 
An eligible impression is one that has successfully communicated with the Ad-server

Measurable impressions
These are ads that are downloaded and stored on user mobile devices and that can actually be measured with  any reporting technology.

Viewable impressions
These refer to ads displayed for more than one second and more than 50% pixels visible that meets the MRC standards.

How to calculate ad viewability
 You can calculate the viewability rate as by dividing the number of viewable impressions by the number of measurable impressions and multiplying by 100.

Viewability Rate = Viewable Impressions/Measurable Impressions

What causes ads to be not ‘viewable’?
Many online display ads end up being shown in ad placements where real users never see them. There are a few reasons that causes ads to be not ‘viewable.’

Ad is not ‘above the fold’ of a web page
The term ‘above the fold’ refers to the top portion of the web page which is visible without a user having to scroll around. Users are viewing web pages using different devices that comes with different screen sizes. When an ad loads below the fold, due to a certain screen size the user is on, the ad is not viewable.

When the user is using an ad blocker
Ad blockers are usually browser plugins that works and helps to hide ads or completely disable them from loading.

Non-human or Invalid Traffic
Another issue that causes an ad to not be viewable is due to non-human or bot traffic. Created by the automation of bots, they can falsify traffic and even click through rates. This is counted as an ad fraud

Why is Viewability Important?
More than half of served ads not getting viewed by users, this made advertisers to waste millions of dollars in ad spend each year. And towards a publisher, this reduced the value of their ad inventory.
According to Google, 56% of ads are not seen by users. To avoid wasting budgets advertiser's consider viewability as an impact factor to make sure their ads are visible to the users.