Identify the Data Problems First
Most reporting mistakes begin before the chart or pivot table. Duplicate rows, inconsistent names, blank values, mixed date formats, and numbers stored as text can quietly distort the result.
Describe the columns and paste a small safe sample into AI. Ask it to list likely cleanup issues and suggest the order in which to fix them.
Create a Cleanup Checklist
Ask AI for a checklist that matches your tool: Excel, Google Sheets, or a CSV workflow. Useful steps might include trimming spaces, standardizing categories, checking unique IDs, and separating combined fields.
Keep the raw data untouched and work on a copy. This gives you a way to compare results and recover if a formula or find-and-replace step changes too much.
Validate Before You Report
After cleanup, compare row counts, totals, date ranges, and category counts against the original file. A clean-looking spreadsheet is not always a correct spreadsheet.
For recurring reports, save the cleanup rules in a notes tab. AI can help write the documentation so the next month does not start from memory.