A buyer should keep evidence that connects four points: what was specified, what the supplier agreed to provide, what was checked when the goods arrived, and how the complaint was handled. The relevant documents, objective observations, inspection or testing records, and correspondence should be retained together rather than as isolated items.
The American Society for Quality recommends providing specifications and other requirements, including testing requirements, when requesting a formal supplier quote. It also includes incoming verification when considering the total cost of dealing with a supplier.
Which records should form the evidence file?
The exact documents will depend on the order, but a practical complaint file can include:
| Evidence | What it should show |
|---|---|
| Quote request and formal quote | The specifications and testing requirements communicated to the supplier, together with the supplier’s response |
| Purchase order and supplier acknowledgment | The order accepted, including product, quantity, quality requirements, and incorporated documents |
| Amendments or change records | Any later changes to specifications, testing arrangements, quantities, or delivery terms |
| Delivery and batch records | Which goods arrived and how they can be linked to the order |
| Incoming inspection or testing records | What was checked, the observations or results, and whether the goods met the stated requirements |
| Photographs and retained samples, where relevant | The condition, packaging, labelling, or other characteristics of the goods at receipt |
| Complaint correspondence | The issue reported, supporting observations, evidence requested, supplier response, and agreed next steps |
| Corrective-action and outcome records | Whether the goods were accepted, rejected, returned, replaced, or otherwise resolved, and any corrective action agreed |
This is a practical recordkeeping checklist, not a statement that every item is contractually or legally required in every situation.
What should be recorded when raising a complaint?
The complaint should identify the affected goods as precisely as available records allow. Useful evidence includes the order or batch reference, delivery information, photographs, inspection observations, and any relevant test results.
Direct observations should be kept separate from conclusions. For example, a photograph may show visible damage, while a conclusion about its cause may require further inspection or testing. Keeping both the original observation and the evidence used to reach a conclusion helps prevent disagreement over what was actually established.
Relevant messages, call notes, delivery documents, and supplier responses should also be retained. A complete trail shows when the issue was raised, what evidence was supplied, what remedy was requested, and how the matter was closed.
How should incoming checks be considered?
Incoming verification is not separate from the total cost of dealing with a supplier. A buyer comparing supplier terms should therefore consider more than the quoted unit price: the resources required to inspect or test incoming goods, handle nonconforming deliveries, and resolve complaints also affect the overall cost.
The buyer should confirm whether incoming checks are required, what will be checked, which evidence will be produced, and who will bear the associated costs. No universal testing method, acceptance threshold, inspection fee, or retention period can be inferred from the cited ASQ guidance.
What still needs to be confirmed?
Before an order is placed, the buyer should check the applicable contract, purchase order, supplier quotation, and official requirements for:
- The exact product specifications and testing obligations
- Inspection methods and acceptance criteria
- Evidence required to substantiate a quality complaint
- Allocation of inspection, testing, return, and related costs
- Batch identification and traceability requirements
- Complaint-response and resolution arrangements
- Retention periods for delivery, testing, and complaint records
- Any supplier-specific conditions for rejection, replacement, or corrective action
The cited ASQ guidance does not establish a universal evidence-retention period, required test, complaint deadline, cost amount, or legal obligation. Those points must be confirmed for the particular transaction rather than assumed.