Fraud & AML
Fraud Rule Review and Calibration in a Banking Environment
Detection thresholds that drifted over time, and a rationale that had to be recoverable the moment a decision was questioned.
Illustrative engagement
The engagement
Where the decision had to hold under scrutiny
Fraud rules were screening for suspicious behaviour across large volumes of transactions, but the basis for individual thresholds had drifted over time. The challenge was not only detection performance, but whether each decision could be understood, reviewed, and defended when a false positive harmed a genuine customer or a missed risk led to loss. Illustrative review work strengthens traceability around rule outputs and identifies where a control’s rationale must be documented. This reduces the chance of an indefensible decision in a high-scrutiny environment.
Key challenges
The problem, and what was done about it
Challenge 01
Thresholds set years earlier no longer matched current fraud patterns, and there was no record of why they had been chosen — so the rule set could neither be trusted nor defended.
What was done
Reviewed each rule against current fraud typologies, recalibrated the thresholds, and re-documented the rationale, establishing a traceable basis for every decision the rules produced.
Challenge 02
Cases that had not actually been assessed were being treated as low risk, blurring the line between a genuine all-clear and a gap in coverage.
What was done
Introduced review discipline that separated assessed-safe from not-yet-assessed, so an unknown was never quietly recorded as low risk and coverage gaps were made visible.
Illustrative — reconstructed from the engagement context
How Verdica makes it defensible
The same five stages, applied to this decision
Every engagement runs the same path. For this one, the weight falls on Trace, Reason, Assure — the stages where a decision of this kind is most often challenged.
Trace
Map every point where the decision could be challenged — before a line of logic is written.
Reason
Build the logic in the open: explainable, deterministic, same input, same output — no black box.
Assure
Validate coverage and oversight before anything ships; nothing unassessed is waved through as safe.
Certify
Lock an immutable, versioned record of exactly what was decided and on what basis.
Evidence
Hand over the audit trail — the pack that holds the moment someone says prove it.
Related engagements
The same standard, holding elsewhere
Discuss a related situation
A decision like this can be made defensible — on the record, not after the fact
A short discussion is usually enough to locate where the risk sits — in the logic, the controls, the evidence, or a combination — and where Verdica makes it hold.