What is validation after transformation?

< 1 min read

Validation after transformation means checking data accuracy before it reaches reporting layer.
I compare row counts between source extract and transformed output.
I reconcile key metrics like total sales, orders, and customers with source system.
Example: After cleaning invoices, daily revenue matched ERP finance report.
I check for unexpected nulls in mandatory fields like Order ID.
I verify joins didn’t create duplicates or drop records.
Sometimes I keep a validation table showing mismatches for QA review.
If differences appear, I backtrack transformation steps to find issue.
Goal is ensuring business trusts the dashboard numbers.

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