Why Northbeam's Attribution Accuracy Keeps Coming Up

Every DTC team that adopts Northbeam eventually hits the same moment. You pull up the dashboard, then pull up Shopify or Meta Ads Manager, and the numbers don't line up. Sometimes it's a few percentage points. Sometimes it's a gap wide enough to make you question the whole report.

That's the real question behind most Northbeam attribution accuracy reviews: why doesn't this match what I'm already looking at?