Three systems know the customer's country and they disagree
Revenue by country differs depending on which model an analyst uses. The CRM, the orders table and the payments provider each hold a country for a customer, and for a meaningful set of customers the three do not agree.
What you would do first
Answer before revealing anything. The value of the exercise is entirely in committing to a diagnosis you can be wrong about.
- 1Quantify the disagreement: how many customers differ, between which pairs of systems, and whether the differences cluster in a segment.
- 2Establish what each system's value actually means and how it is updated — that usually explains the pattern immediately.
- 3Ask each consumer which meaning their question needs. Tax reporting, shipping and market analysis want different answers, and all three are legitimate.
- 4Check whether any model silently picks one, which is where the current inconsistency comes from.
What is actually going on
The trap
The fix that looks right. Read it even if you got the answer — especially then.
Coalesce the three, preferring whichever was updated most recently. The number stops changing between models, the attribute now has no definable meaning at all, and every downstream analysis is grouped by a field that is billing country for some customers and shipping country for others.