Consent Mode v2 modeled conversions: bid on them, or report only the consented count?

A cookie banner can hide a big share of EU conversions, and Consent Mode v2 is meant to win some of that back through modeling. The catch is that the model only learns from users who accepted. If the decline rate is high and skewed toward mobile or one country, the modeled numbers can drift a long way from what actually happened. Bidding on them is probably fine as long as you track the ratio of modeled to consented conversions every week. If that ratio swings a lot, the model is guessing, not measuring. What decline rate would you say is too high to trust the model at all?

Not sure there's a clean cutoff. What I'd check is whether the declines are spread evenly or piled up on one device or region. A random 40% decline is easier to model than 15% concentrated on iPhone Safari. For a local plumber with traffic from one city, that split often matters more than the overall rate.