Viewability

Viewability is a vendor measurement of whether an impression was in view under that vendor's rules (area and time). The report fields live next to IVT on the same performance view we already query: viewable_impressions, viewability_percent, and related timing fields.

Those fields return zero when no measurement add-on is attached to the creative. That zero is not "nobody saw it" and not "everyone saw it." It is "we did not measure." Adprime Zero campaigns ran with empty creative add-ons for months. We will not publish a viewability rate until a vendor tag is on and the fields are non-zero.

Viewability is not CTR and not click-to-page-view. An in-view impression can still produce a junk click. A click can come from inventory that was never in view by the vendor's standard.

Until the tag is on, do not optimize remnant toward viewability stories. Use concentration and visits. The plan to publish rates later is IVT and viewability once measured.