Viewability is tracked through a JavaScript deployed at the time of the rendering of the ad, at an interval of 1 second. The "measured" rate indicates what rate of impressions have been successfully tracked for viewability. An ad impression is viewable when
either more than 50% of the ad surface is viewable to the user for at least one second.
or more than 30% of the ad surface of an ad of at least 242 500 pixels is viewable to the user for at least one second.
We do not attempt to track viewability for
ads marked as expandable
ads in cross domain iframes