Sampling chargebacks without drowning in noise
How to design a chargeback sample that tests reporting accuracy rather than dispute quality alone.
Chargeback reporting accuracy is a different question from win-rate. Accuracy asks whether every dispute that hit the processor also appears in your operations ledger with the right reason code, amount, and status date.
Stratify samples by scheme, reason family, and age band. For each selected case, confirm the trail from processor notice to ledger entry to merchant notification. Missing notifications often explain why finance reports look clean while merchant complaints rise.
Document the population size and selection method in the workpaper. Examiners and external auditors care as much about how you sampled as about the exceptions you found.