To verify the correctness of data transformation against the signed off business requirements and rules.
• To verify that expected data is loaded into a data mart or data warehouse without loss of any data.
• To validate the accuracy of reconciliation reports (if any e.g. in case of comparison of report of transactions made via bank ATM – ATM report vs. Bank Account Report).
• To make sure complete process meets the performance and scalability requirements
• Data security is also sometimes part of ETL testing
• To evaluate the reporting efficiency