What document should include acceptable vendor viewability thresholds?

The correct document that should include acceptable vendor viewability thresholds is the insertion order (IO). An IO is a contract between the advertiser and the publisher that specifies the details and conditions of the advertising campaign, including key performance indicators such as viewability rates. Since viewability thresholds are critical for measuring the effectiveness of an ad campaign and ensure that the ads reach the intended audience in a measurable way, they are explicitly outlined in the IO to establish expectations and deliverables between both parties.

The request for proposals (RFP) focuses more on the overall requirements and goals of the campaign rather than detailed operational specifics. The media plan typically outlines the strategy and placements but may not provide the granular specifications needed regarding viewability. Meanwhile, the creative brief centers on the creative aspects of the campaign and does not usually delve into the operational metrics like viewability thresholds.