Meta and Google can participate in the same buying journey. Budget decisions still need to distinguish a plausible interaction from measured incremental contribution.
A person may encounter a creative, search for the brand, compare a product, return through another ad and purchase. Each platform can assign credit under its own rules. Their reports are not a deduplicated business ledger and do not independently prove which touch caused the order.
Treat the channel relationship as a hypothesis. A strong platform ratio or a rise in brand searches does not establish incremental contribution or mean that either channel must always remain funded.
Agree on the transaction record, costs, comparison window and customer definitions. Where feasible, use an appropriate holdout or geo experiment; otherwise retain the confounders and describe association accurately. Connect creative and destinations across channels while allowing the evidence to show that a particular activity should be changed or stopped.
Take the idea further
Choose the cross-channel test