Sampling Vendor Spend Without Chasing Noise
A useful procurement sample is not a random scoop of every invoice. We usually split the population into high-value vendors, newly onboarded suppliers, and a thin random layer of everything else. That mix catches rate drift on long relationships and also the one-time vendor created for a single payment.
Controllers sometimes ask for “100% testing.” In practice that burns weeks on low-risk stationery spend while the packaging contract that moved 8% above tender rates sits untouched. Agree the strata with internal audit before fieldwork starts; it keeps the finding register focused on decisions the board can act on.