Why Are Video Completed Views Higher Than Video Impressions in Reporting?

It’s not uncommon to see instances where video completions or player starts are higher than the number of impressions in reporting. At first glance, this may not make sense — logic would suggest that a video must be served (triggering the impression), then played (player start), and finally completed (completion event). However, that sequence isn’t always followed due to how video players behave.

The Reason: Player Interpretation of VAST Events

These discrepancies are often caused by what’s known as Player Interpretation.

Here's how it works:

• A VAST tag includes a set of tracking events (such as impression, start, pause, complete).

• These events are sent by The Trade Desk (TTD) through a VAST wrapper.

• However, TTD does not control when these events are triggered — the video player does.

Each VAST player (used by publishers) interprets the VAST spec slightly differently. That means:

• A player might fire an impression without a start.

• It might fire a start without an impression.

• It could fire multiple impressions and only one start.

• It could even fire a completion without an impression.

The combinations vary depending on how the player is built and configured. TTD simply records the events it receives, but does not control when they happen.

Does This Impact Reporting?

Fortunately, no — these discrepancies are common across the industry and generally:

• Do not impact billing

• Do not significantly affect overall campaign performance

• Are purely the result of how third-party video players trigger tracking events