- Poor transformation introduces wrong aggregations and duplicate records in reports.
- Incorrect joins can multiply sales rows and inflate revenue numbers.
- Missing filters may include cancelled or test transactions in KPIs.
- Wrong date handling shifts data into incorrect months or quarters.
- Example: Order date vs invoice date confusion changed monthly revenue trend.
- Null handling issues can drop customers from retention calculations.
- Different reports show different totals, causing stakeholder confusion.
- Business decisions like targets and bonuses may be based on wrong data.
- Overall accuracy drops and trust in BI reporting decreases.
How does poor transformation affect reporting accuracy?
Updated on February 11, 2026
< 1 min read
