Viewability is a red hot topic in the ad tech space right now.

But why now?

Well, there are multiple market forces in ad tech that have created a need for industry-wide adoption of viewability and standard viewability metrics:

  1. Ad buying –  More and more ad sales are being transacted programmatically rather than via direct sales models. In fact, programmatic display ad spending is forecasted to account for 72% of all display ad spending by 2017, up from just 49% in 2014.

viewability programmatic sales

  1. Measurement – Both publishers and buyers are zooming in on their performance, moving from campaign-level performance metrics to impression level analysis.
  2. Buying focus – Savvy buyers are no longer looking for scale alone. They want high quality inventory and impressions for all their campaigns, and more than ever, they want to know that their ads are being seen.

Programmatic is gaining momentum, creating a wellspring of impression-level data that allows buyers and publishers to really dial in the quality of their programmatic partnerships and campaigns. This focus has created the need for more comprehensive ways to measure on page engagement and viewability at the user and impression level.

Enter: Viewable Engagement Time, or VET.

What is Viewable Engagement Time (VET)?

Created by the viewability obsessed team at OnScroll, VET is a user-engagement metric that enables publishers to sell inventory on their website based on user engagement rather than impressions alone.

VET is powered by 10+ activity events that are collected on page through VET-enabled ad tags. VET also tracks whether or not ad units themselves are in view by measuring if at least 50% of the ad pixels are in the viewport. Clicks, scrolls, tab changes and other user actions are aggregated to determine, at any given moment, if, where and how a user is engaged on the page.


Viewable Engaged Time also allows publishers to call a subsequent ad to fill as a reloaded creative after a pre-defined VET threshold has been met. By enabling Viewable Engagement Time, a publisher can serve multiple impressions per pageview for ad zones that are verified as in-view of an active reader.


viewability viewable engaged time

How does VET compare to standard display and viewability models?

In the push to move to a viewable model for all ad serving, the basic math is not always favorable to publishers.

With the standard display model of ad serving, the amount of available inventory is calculated based on the static number of ads per page and the number of impressions to that page. With the standard viewable model, the viewability rate (or viewability score) is multiplied to impression inventory to provide the final amount of inventory for that page. If the viewability rate is below 100%, the total inventory rate will decrease.


viewable engagement time


With VET, the viewability score is also taken into account, but there is also the reload rate to take into account. Every VET-enabled zone on the page is eligible to reload a new creative after 20 seconds of VET. Thus, the available inventory actually increases, generating additive revenue for the publisher.

What this simple explanation doesn’t take into account, however, is the potential increase in CPM for guaranteed viewable inventory. Most viewable inventory is bought through Deal IDs, which tell participating buyers which requests are guaranteed viewable, along with their viewability rate, using specific identifiers in the ad request code.

Why does it matter that viewable inventory is sold via Deal IDs?

Because buyers know exactly which inventory is viewable, ad exchanges like Sovrn are able to set floors based on the value of that inventory. These floors range anywhere between $2.50 and $5.00, which eCPMs often coming in much higher.

What are the benefits of Viewable Engagement Time?

Well for starters, VET has major revenue impacts for publishers using the technology. Sovrn OnScroll publishers utilizing VET technology have seen an average lift of 56% in programmatic revenue and 51% average lift in inventory.

“On average, Viewable Engagement Time technology delivers 56% lift in programmatic revenue and 51% lift in inventory.”

But the nuanced piece of VET and it’s impact on revenue comes to pricing and quality.

With VET, pricing has a clear minimum and maximum quality threshold for inventory. At minimum, eligible ads must be at least 50% in view for 1 second or more. At maximum, 50% of the ad is in view for the configured VET reload time, generally 20-30 seconds.

Thus, buyers are given greater confidence in the delivery of their ads. They can buy based on guaranteed viewability and (in the near future) reap the benefits of all user engagement reporting from VET. And publishers who are creating engaging content are rewarded for the stickiness of their work.

VET will soon be available for all Sovrn ad units in Meridian. Stay tuned for more content about viewability and for updates about the new VET technology to come.

Ready to get started with in view ads on your website? Sign up for Sovrn today!

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