Viewability

How Viewability Works

Viewability emerged as a critical metric after research revealed that a significant percentage of digital impressions were technically served but never visible to any human. Studies prior to viewability standards found that roughly 50 percent of display ads were below the fold and never scrolled into view. The Media Rating Council, supported by the IAB, established the current viewability definition in 2014: for display ads, 50 percent of the ad's pixels must be within the browser's viewport for at least one continuous second. For video, the threshold is 50 percent of pixels in view for two continuous seconds.

Why Viewability Matters for B2B Marketing

Viewability is measured by JavaScript tags placed within the ad creative or by verification vendors like Integral Ad Science (IAS), DoubleVerify, and Moat. These tags continuously measure the ad's position relative to the browser viewport as users scroll. The measurement is sent back to the verification platform, which calculates the viewability rate as the percentage of total served impressions that met the MRC threshold. Viewability rates are then reported at the campaign, placement, and publisher level.

Viewability: Best Practices & Strategic Application

Industry benchmarks for viewability vary by format and channel. Google's Active View data historically showed average display viewability of about 50 to 55 percent across the open web, while premium publisher direct buys and PMP deals typically achieve 65 to 85 percent. Video formats naturally achieve higher viewability because they are larger and users are more likely to engage. Above-the-fold placements, sticky units, and in-content ads consistently outperform below-the-fold and sidebar placements.

Agency Perspective: Viewability in Practice

Advertisers increasingly negotiate viewability guarantees into direct and PMP deals, requiring publishers to maintain minimum viewability rates — typically 70 to 80 percent — or provide make-good impressions. In programmatic campaigns, DSPs allow buyers to filter inventory by predicted viewability score, ensuring spend is allocated toward placements with strong track records of viewability. The IAB's "Making Measurement Make Sense" initiative recommended a 70 percent viewability threshold as the standard for transacting, though adoption of this higher standard varies by buyer.