Glossary
What is Video quartiles?
Also called: quartile events, quartile tracking
Video quartiles are the tracking events a player fires as an ad plays: at 25% (first quartile), 50% (midpoint) and 75% (third quartile).
हिंदी में पढ़ेंA VAST response lists tracking links for each stage of a video ad. The player calls the impression link and fires start when the ad begins, then firstQuartile at 25%, midpoint at 50%, thirdQuartile at 75% and complete at the end. These are the quartile events.
They tell the buyer how far each ad played, not just that it started. Counting them gives a drop-off curve for your player: how many viewers stayed to each point. The last step, completes divided by impressions, is the completion rate.
Quartiles measure how much of the ad played, not whether anyone could see it. A video ad is viewable under the IAB and MRC standard when at least 50% of the player is on screen for two continuous seconds, so read quartiles alongside viewability. When an ad cannot play at all, the player reports a VAST error code instead.
Example
1,000 video ads start. 820 reach the first quartile, 700 the midpoint, 610 the third quartile and 540 complete. The completion rate is 540 ÷ 1,000 = 54%, and the biggest drop, 180 viewers, comes before the first quartile.
Why it matters to publishers
Quartiles show where viewers drop off, and buyers use the same numbers to judge your video inventory.