The Programmatic Glossary
A practical glossary designed to help marketers, advertisers and ad-tech professionals understand the terminology that powers programmatic advertising
Measurement & Analytics
Viewability
A measure of whether an ad had a genuine opportunity to be seen by a human user. An ad that loads at the bottom of a page that no one scrolls to is technically an impression but has zero viewability. Viewability standards help advertisers pay only for ads that could realistically have been noticed.
HOW IT WORKS
The IAB (Interactive Advertising Bureau) standard for display viewability is: at least 50% of the ad's pixels must be in the visible part of the browser window for at least one continuous second. For video, it is 50% of pixels visible for at least two continuous seconds. Measurement vendors such as IAS and DoubleVerify use JavaScript to track this in real time.
EXAMPLE
A advertiser runs a campaign and pays for one million impressions. Viewability measurement reveals that only 58% were viewable by IAB (Interactive Advertising Bureau) standards: 420.000 loaded below the fold and were never in view. They renegotiate with publishers, shifting budget to above-the-fold placements with guaranteed 70% or higher viewability.
RELATED TERMS
Impression | Video Completion Rate (VCR) | Invalid Traffic (IVT) | CPM | Brand Safety
★ LIMELIGHT INSIGHT: Limelight supports integration with leading viewability measurement vendors including IAS and DoubleVerify, helping advertisers verify the quality of impressions served across publisher inventory.
