But these changes aren’t coming out of nowhere.
Facebook hinted back in August, when it shared initial guidance on how to prepare for iOS 14, that it would likely no longer be able to measure mobile app installs and other app events from iOS 14 devices in conversion lift tests.
When an iOS 14 user opts out of tracking, Facebook has said it will honor that choice across browsers and devices, which means Facebook won’t be able to track the behavior of the control groups over time.
“This is a significant decision proactively made by Facebook to honor a user’s privacy consent, but it has widespread negative impact across all of Facebook’s advertising products and, markedly, to attribution,” said Bharadwaj, who noted that he’s heard chatter that Facebook is working on a way to estimate attribution for non-consented users.
For now, advertisers can still run an A/B test without a holdout to see…