Finding 01
Measurement
Meta was taking credit for sales it didn't cause
What we saw
Meta's own incremental model credited only about two thirds of the purchases the account reported, and almost 3 in 10 purchases were 1-day view.
Why it matters
Budget decisions were being made on a ROAS number that overstated what the ads were doing.
What to do
Manage to Shopify cost per new customer and treat Meta-reported ROAS as a directional signal only.