Respuesta de referencia
When someone says the numbers are wrong, I don't assume the report is broken. I narrow the gap first.
I start by asking for the exact metric and time period where the mismatch occurs. I ask them for the number they see in the source system and how they calculated it. Without a precise comparison, troubleshooting becomes guesswork.
Next, I check data freshness. I look at the dataset refresh history in Power BI Service and confirm when the last refresh ran successfully. Many discrepancies come from stale data or failed refreshes.
After that, I check filters. I review report-level, page-level, and visual-level filters in the Filters pane. I also look at slicers that might be affecting the numbers. Sometimes, a hidden filter or a default slicer selection explains the difference immediately.
If filters are not the issue, I move to the DAX measure. I read the formula carefully. I look for CALCULATE statements that add filter conditions. I check whether DISTINCTCOUNT is being used instead of COUNT, or whether blanks are being excluded implicitly. Even small filter conditions inside a measure can change totals significantly.
Then I inspect the data model. I verify relationships, cardinality, cross-filter direction, and whether any many-to-many relationships exist. Incorrect relationships can duplicate rows or filter out data unintentionally. If I suspect duplication, I test counts at the table level to confirm.
After that, I review Power Query transformations. I check whether rows were removed during cleaning, duplicate removal, error filtering, or type conversion issues that can drop records silently. I compare row counts before and after major transformation steps.
If the issue still isn't clear, I go to the raw data. I export the data from the visual and run an equivalent SQL query against the source system. Then I compare the results row by row. That usually reveals whether the difference comes from transformation logic, modeling, or calculation rules.
Once I identify the root cause, I document it clearly. I explain what caused the mismatch, whether it was a refresh delay, filter logic, relationship configuration, or business definition difference. If the report logic needs correction, I fix it. If the issue comes from differing metric definitions, I align with stakeholders and update the documentation so the same confusion doesn't happen again.
Hence, this is what I do in short: I define the gap precisely, validate freshness and filters, review DAX and relationships, inspect transformations, and verify against raw data before concluding.