UA Ledger · Measurement Lab · draft for review

Find repeated purchase records before reporting revenue

Synthetic teaching inputs. No real campaign results or industry defaults. Change the values to inspect the model. Calculations run locally; this page sends no data and does not retain inputs after closing.

Start with records already restricted to one transaction system, currency and reporting period. Compare raw purchase rows with distinct transaction identifiers. Count a repeated identifier as an investigation candidate, preserving its original rows so that legitimate split records can be distinguished from accidental replay. Do not deduplicate every event by timestamp: separate events can share a timestamp, and a transaction key has a different meaning.

Calculated outputs

Assumption sensitivity

Only rows varies; all other inputs are held constant. This is not a probability range.

Equations

• Excess rows: rows-unique
• Excess row share %: 100*(rows-unique)/rows

Additional constraints: (unique<=rows). The field minimums also apply.

Limits

A stable, correctly scoped transaction identifier is required. This calculator does not inspect IDs, establish which rows are erroneous, or prove that a vendor already deduplicates them.

Measure ecommerce: purchases and refunds · primary documentation checked 19 September 2026.