Institute of European Standards and Quality 
The purchasing question
Supplier quality work should support a specific decision: selecting a supplier, understanding a process risk, assessing a change or reviewing evidence against a purchasing requirement. That decision determines the appropriate scope and level of detail.
Project scope
A project may examine specifications, supplier controls, production information or the treatment of nonconformities. The scope identifies the supplier, product or service, relevant sites and period. It also identifies whether the work serves a particular purchaser.
Criteria and method
Evaluation criteria may come from a contract, specification, recognised standard or agreed framework. The method explains how evidence is selected and considered. Supplier statements, sample records and observations are distinguished in the analysis.
Information and access
The parties identify the information available, the access required and confidentiality obligations. Documents should relate to the actual product, process or purchasing requirement. Restrictions affecting the strength of a conclusion are recorded.
Work stages
The project proceeds from scope agreement to information review and the agreed evaluation activities. Findings are discussed for factual accuracy without allowing the evaluated party to determine an independent conclusion. Material scope changes require agreement.
Report and follow-up
The report records the question, criteria, evidence, findings and limitations. Follow-up may examine whether agreed action addresses the original issue. A report for one customer's purchasing purpose is not automatically a public certificate for wider use.
Interests and other services
Consultancy, internal audit and third-party certification can create different relationships with the same organisation. Those relationships require consideration before an assignment is accepted. A separate page, team name or invoice does not resolve a substantive conflict.
Discuss a supplier project
Identify the purchasing decision, supplier activity, relevant requirements and available evidence. Indicate who will use the report and whether any part of it is intended for public disclosure.