A protocol for measuring supplier-statement coverage

Coverage cannot be calculated from the documents that happened to arrive. Freeze a supplier-period population from a dated accounts-payable extract using a written rule, such as vendors with activity or an open balance during the period. Record entity, vendor ID, period, activity, closing balance, whether a statement is expected, and the responsible contact.

Separately identify intercompany counterparties, employee reimbursements, card providers, one-time payees, or other groups that use a different evidence process. Preserve the unaltered export, filter logic, extraction time, row count, and control total. Adding only suppliers that sent statements would create a circular denominator.

Track statements requested, received by cutoff, and usable for the defined comparison as separate states. A usable document should identify the supplier, covered period, and enough transaction or balance detail for the procedure. Record how it was obtained and any authenticity or completeness concern.

PCAOB AS 1105 supplies an audit-context principle: reliability varies with source, nature, and circumstances. PCAOB AS 2310 draws a further boundary around auditor-controlled external confirmations. An emailed or portal statement collected in routine bookkeeping may be useful external evidence, but it is not automatically a confirmation under that standard. This protocol makes no audit claim.

For each usable statement, compare supplier identity, statement date, opening balance, invoices, credit notes, payments, adjustments, and closing balance with the ledger. Preserve gross movements so offsetting differences are visible. Link every discrepancy to the statement line and ledger reference.

Use observable categories such as cutoff, missing invoice, missing credit, unapplied payment, duplicate, disputed charge, entity mismatch, currency issue, and unresolved. Do not force an unexplained item into a timing category. A preparer can perform the documented comparison; an authorized finance owner decides whether to post an entry, accept a credit, dispute a charge, or release payment.

Use the frozen eligible supplier-period count as the denominator and show, in sequence, expected statements, requests sent, documents received, usable documents, comparisons completed, differences identified, and owner decisions completed. Also report request age and unresolved counts where timestamps are reliable. Each measure needs its own numerator rather than one composite percentage.

A higher usable-statement share may create more opportunity to observe differences, but this article does not claim that collection causes a more complete ledger. Agreement with statements also cannot prove completeness because documents may omit transactions, use another cutoff, or contain errors.

Reason codes can include supplier does not issue statements, contact unavailable, portal access unavailable, request outstanding, received after cutoff, no longer eligible, or approved alternative evidence used. Retain follow-ups under the supplier-period ID. Missing evidence is a queue condition, not proof that a liability exists or does not exist.

GAO's Green Book supports assigned control responsibility and quality information in its government-control setting; it does not prescribe supplier-statement collection. The accounts-payable owner should approve eligibility and alternatives, and a second reviewer should retest samples of included and excluded suppliers plus selected comparisons.

Supplier populations differ by industry, payment channel, entity structure, and system design. Statements can be unavailable, incomplete, altered, or prepared to different dates. Repeated supplier-period observations are related, small populations can exaggerate rare outcomes, and a coverage percentage says nothing by itself about monetary exposure.

A report should disclose the eligibility rule, cutoff, statement expectation, covered entities and systems, acquisition channels, usable-document rule, alternatives, unresolved differences, and owner decisions. Privacy and access constraints may limit retention. Accounting, tax, legal, and payment decisions remain outside the coverage calculation.