You run Meta ads to your Shopify store. You also run them to your Amazon listings. Or maybe the same campaign drives traffic to both, depending on where the shopper ends up clicking through. Either way, Shopify's dashboard only sees one side of that split.

That's the core issue behind Amazon attribution for Shopify brands explained: your ad spend gets credited to whatever converts in Shopify, and anything that converts on Amazon instead looks like organic, unpaid traffic on Amazon's side. Free money, as far as your reports are concerned. It isn't.