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Practice
Identify a confirmed exact duplicate
Two rows share order_id O-401, order date 2026-08-02, revenue $100, and extract batch B17. The source owner confirms one was copied twice. How should they be classified?
Confirmed duplicate · cleaning reconciliation
A controlled removal changes rows and revenue predictably
Row control
Raw4 rows
Clean3 rows
Revenue control
Raw$335
Clean$235
The $100 difference equals the one confirmed extraction duplicate; the raw layer and cleaning log remain preserved.