Full Answer

ROAS drops look like a creative problem or audience problem. Usually they're a data problem. Meta's delivery algorithm optimizes for the signals you give it — if those signals are incomplete, targeting degrades gradually without any visible warning.

Data loss causes: iOS 14.5+ ATT opt-outs reduce Meta's ability to attribute cross-device conversions. Safari ITP limits fbclid cookie to 24 hours. Ad blockers block Meta Pixel for 31.5% of users globally. The result: Meta sees fewer conversions, builds lookalike audiences on a smaller pool, and starts showing ads to lower-intent audiences.

Algorithm causes: Each significant campaign edit resets the learning phase. Too many ad sets fragment conversion volume below the 50-events-per-week threshold. Meta needs clean, consistent conversion signals to stabilize delivery.

Fix: Implement Facebook CAPI server-side to recover lost conversions. Consolidate ad sets. Don't edit campaigns during the learning phase. Better data in = better ROAS out.