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What Makes a Viewable Impression? Publisher’s Guide to Ad Viewability Standards

Viewability matters for publishers. Google Ad Manager data shows that increasing ad viewability from 50% to 90% results in an 80% increase in revenue. That’s an impressive increase. But what is viewability, exactly? The answer to that question is more nuanced than it would seem.

In the most basic sense, ad viewability is simply how visible ads are to users. The standards and measurement tools around viewability have evolved over time to help publishers and advertisers better transact on viewability campaigns. Now, it has become less of a bespoke KPI and more of a transactional metric that is considered table stakes by most advertisers.

The need for viewability tools came into focus in 2014, when a report by Google found that a staggering 56% of digital ads were not seen by a human. This revelation understandably troubled advertisers, and publishers were then tasked with providing a set of metrics that could quantify the viewability of their inventory. So the industry set to work.

Viewability Standards Are Set

That same year, the Media Rating Council (MRC) in conjunction with the Interactive Advertising Bureau (IAB) released a set of viewability standards that aimed to address this issue. The new standard set was that 50% of a display ad’s pixels must be in view for at least one second. In 2015, standards were added for video (50% in view for two seconds), and in 2016 mobile standards were issued as well.

It was by these standards that Google launched its Active View technology to measure viewability and integrated it into its suite of Google Ad products. Google’s viewability metrics are calculated by weighing viewable impressions (i.e. ad impressions that meet the MRC set standards) against measurable impressions and overall eligible impressions (those being ads with the Active View tag that have communicated with Google’s servers).

But viewability standards continued to evolve. In particular, agencies began releasing specific standards, building on the MRC and IAB standard. Some agencies set standards requiring that impressions be 100% in-view and for video, 100% in-view with 50% of the ad played with sound-on (and autoplay doesn’t count).

Key Advertising Viewable Standards and Definitions

To break down these differences in a helpful table, we first have to summarize a few key definitions:

  • Measurement: What is a viewable impression
  • In-View: How much of the ad must be visible
  • Timing: How long the ad must be visible for

Interactive Advertising Bureau (IAB)

What It Is Measurement In-View Timing
A base guideline for impression viewability measurement standards. The foundation on which other standards build upon.

Ad impressions are counted when they are loaded and displayed per IAB Ad Impression Measurement Guidelines, and in accordance with their set viewability standards. Ads must be displayed within a web browser window, ads displayed outside the browser window do not count.

Display: 50% of pixels must be in view.

Video: 50% of ad in view.

Display: Ad must be in view for one second.

Video: Ad must be viewed for two seconds.


Media Rating Council (MRC)

What It Is Measurement In-View Timing
Updated viewability standards that take factors into consideration not expressly outlined in IAB standards.

MRC standards start with the IAB foundation defined above, but will also consider an ad viewable if there is “strong interaction” (such as a click on the ad).

Display: 50% in view, and 30% in view for large ads above 242,500 pixels

Video: 50% in view.



Display: Ad must be in view for one second, regardless of ad size.

Video: Ad must be in view for two continuous seconds at any point during unduplicated content of the ad. Click-to-play ads initiated by the user must be in view for the first 200 milliseconds.


Google Active View

What It Is Measurement In-View Timing
Google’s ad viewability technology that measures viewable impressions within the Google Advertising suite. Active View uses IAB and MRC guidelines in considering viewability.

A viewable impression is one that is tagged and measured within Google Active view by MRC viewability standards

Display: Ad must be in view for one second, regardless of ad size.

Video: Ad must be in view for two continuous seconds

Display: Ad must be in view for one second, regardless of ad size.

Video: Ad must be in view for two continuous seconds



Agency Specific

(Not representative of all agencies)

What It Is Measurement In-View Timing
A set of standards that are often more stringent than IAB and MRC’s defined standards in what counts as a viewable impression.

Specific agencies opt to only count an ad impression as viewable when it meets their defined in-view and timing standards.

Display: Ad must be 100% in view.

Video: Ad must be 100% in view, with sound on. User must click to initiate the ad - autoplay does not count.
Display: Ad must be in view for one second.

Video: Ad must be in view for half of the duration of the ad.



These competing standards began to burden publishers with the need to create and redesign ad units to fit within IAB, MRC and Agency standards. Measuring the viewability and performance of these ad units became an added challenge. While ad tech rose to help marketers measure and analyze the effectiveness of these new standards, publishers often received secondhand information about the viewability of their inventory. This led to frequent buffering and makegoods to cover viewability issues that were not easy to diagnose and fix in real-time.

To help improve viewability industry wide, the sell-side needs data and improved transparency. Measuring individual ad unit viewability across platforms, devices and browsers would give publishers the ability to diagnose and improve viewability before it negatively impacts revenue or buyer campaign performance.

Request a demo to learn how your organization can better measure and optimize for viewability with DV Publisher Suite.