Duplicate Detection
Definition
A systematic search for records that share key fields (invoice number, vendor, amount, date) that should be unique, surfacing duplicate payments, double invoices, or parallel processing of the same expense.
- Method
- Computer-Assisted Audit Technique (CAAT)
- Matched fields
- Invoice number, vendor, amount, date
- Surfaces
- Duplicate payments, double invoices
Common questions
Why does duplicate detection match on combinations of fields rather than one field alone?+
Matching only invoice number would miss duplicates entered with a typo, while matching only amount would flag many unrelated legitimate payments. Combining fields such as vendor plus amount plus date range balances catching real duplicates against generating excessive false positives.
Does a flagged duplicate always indicate fraud?+
No, many flagged duplicates turn out to be legitimate, for example a vendor resubmitting a corrected invoice or two separate but similarly priced purchases. Each flag requires manual review before being treated as a control failure or fraud indicator.
Related terms
- CAATs
- Computer-Assisted Audit Techniques: software-driven procedures applied to electronic data files that test the full population of transactions rather than a sample, covering...
- Gap Test
- A test that identifies missing numbers in a document sequence (check numbers, invoice series, purchase orders) where continuity is expected; gaps often...
- Join-and-Match
- A cross-table technique that links two or more data files on a common key, such as matching vendor bank account numbers against...
- Ratio Analysis
- Calculation of financial ratios across periods or business units to identify statistically unusual deviations that might indicate manipulation: cost ratios, gross margin...
- Sequence Analysis
- Verification that a numbered series progresses in expected order without skips, reversals, or unexpected repetitions. It is the positive counterpart to gap...
- Stratification
- The grouping of numeric values into defined ranges (strata) to reveal the distribution of a dataset. In fraud detection, large concentrations of...