The Problem with Ad Viewability: Where’s the Performance?

Sovrn Advertising Team // November 1, 2021

In the online advertising space, publishers and advertisers alike rely on their ability to measure potential value when pricing and bidding on ad inventory. For years, viewability has been the industry standard for predicting ad performance – but our research shows there may be a better way.

Viewability is intended to measure the likelihood that an ad will be seen by users, based on whether it is visible on the page. As defined by the IAB, a viewable impression is one where at least 50% of the ad’s area is displayed onscreen for at least one second. While this is useful for measuring ad inventory quality, it doesn’t go far enough to demonstrate performance because it fails to consider whether the ad is actually seen or noticed by the reader.

Engaged Time – the Better Measure of Reader Attention

We’ve devised a metric to better measure reader attention, Engaged Time. Engaged Time combines viewability with 45 distinct on-page user interactions – including page scrolls, mouse clicks, keyboard activity, and more – to measure both 1) when an ad has the chance to be seen and 2) when a person is actively engaged with the content. The result is a truer measure of a reader’s attention – and a metric that delivers more than double the attention (2.6 times) and direct response (2.1 times) of viewability alone.

Let’s dig into the research

We recently harnessed the power of Signal to test how Engaged Time impacts ad performance in two recent studies:

Study 1: Engaged Time and attention

In August and September 2021, Sovrn partnered with demand side platform Avocet and attention technology company Lumen to study* the correlation between Engaged Time and attention. Using Lumen’s eye tracking data and predictive modeling, as well as Sovrn’s Signal technology, the study analyzed more than 3 million global impressions and 100 ad units to identify signs that a reader actually looked at an ad while it was in view. We then compared the difference in attention between Engaged Time and viewable time (Chart 1). The study revealed that Engaged Time captures 2.6 times more attention than viewable time. Chart 2 shows this uplift over time.

Chart 1
Chart 2

Study 2: Engaged Time and direct response

In a separate study** conducted in October 2021, Sovrn compared Engaged Time and viewable time using click-through rate as the performance metric. Using our Signal technology, we tracked more than 3 billion impressions across 2,000+ publishers on the Sovrn platform, measuring the amount of time that each tracked impression was in view versus the amount of time the same impression was in view with an engaged reader. We then compared the difference in click-through rate between Engaged Time and viewable time (Chart 3). Across a variety of devices, we found that Engaged Time captured an average of 2.1 times higher direct response than viewable time.

Chart 3

Embracing Engaged Time Benefits the Advertising Marketplace

Today’s advertising ecosystem has few clear standards and best practices for measuring attention. As a result, many advertisers have created their own custom scoring systems. Not only is this inefficient for advertisers, but it also puts publishers at a disadvantage because they don’t know what measurements ad buyers are applying to their bids. 

Embracing Engaged Time as a standard measure of ad performance eliminates this issue, and provides clear benefits for both publishers and advertisers: 

For publishers, it provides a way to: 

  • understand how users engage with content so they can improve page layouts and user experience 
  • identify and price their most valuable ad inventory 
  • drive more revenue from engaged visitors

For advertisers, it offers:

  • a consistent, meaningful basis for bidding on ad inventory 
  • allows advertisers to optimize ad spend
  • drives brand awareness and direct response among a more engaged audience

Benefit from Engaged Time with Signal

Sovrn’s Signal technology equips publishers with tools to measure, compare, and monetize both viewability and Engaged Time. This intelligence is currently available for advertisers across Sovrn’s website and publishers who work with Sovrn. To learn more about our Signal technology, visit

Study Methodology

*Awareness: Commissioned research by Avocet and Lumen used eye tracking data and predictive modeling, as well as Sovrn’s Signal technology, to analyze more than 3 million global impressions and 100 ad units across a broad range of categories. This research was conducted over four weeks during August and September 2021.

**Direct response: Proprietary research by Sovrn used the Signal technology to track more than 3 billion impressions across 2,000+ publishers on the Sovrn platform. This research was conducted over seven days during October 2021. 

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