Journal
Sampling methods for transaction monitoring reviews
Datalinkbox field note · ~9 min
Transaction monitoring controls fail in two common ways: alerts that never get investigated, and investigations that never touch the risk that triggered them. Your sample design has to pick which failure you are testing—or run two tests.
Alert-population samples
If the claim is “every high-severity alert is reviewed within the SLA,” your population is the alert queue, not the payment ledger. Stratify by severity and aging. Document how suppressed or auto-closed alerts are treated so reviewers cannot accuse you of sampling only the easy cases.
Underlying transaction samples
If the claim is “suspicious patterns are detected,” you may need a sample of transactions that should have alerted under the rule set. That is a different, often harder, test. It requires rule logic access and a clear definition of “should have alerted.”
Avoid double comfort
Do not cite an alert-queue sample as proof that detection works. Detection effectiveness and investigation discipline are sibling claims. In our Corridor Sampling Intensive materials, we force teams to label which claim each sample supports before they pull data.