A pre-shipment inspection (PSI) checks a defined sample of finished goods before shipment. Its purpose is to give the buyer evidence for a release decision while the goods are still accessible at origin.
A PSI cannot repair a weak specification or guarantee every unit. It works when acceptance criteria were agreed before production and the inspector has the correct references, tools, and sampling instruction.
Decide when the inspection can occur
The normal PSI point is when production is complete and most goods are packed for shipment. If inspection occurs too early, the sample may not represent the final lot and packaging may be unavailable. If it occurs after the container is sealed or balance payment is irreversible, the buyer has less practical leverage.
Set a readiness rule in the purchase order, such as 100% production complete and at least 80% packed, adjusted for the product and inspection plan. Require the supplier to confirm quantity and readiness before the inspector travels.
For higher-risk orders, a PSI may be one layer in a broader plan that includes pre-production review, first-article approval, during-production inspection, laboratory testing, and container-loading supervision.
Give the inspector a controlled document pack
Provide:
- purchase order and product revision;
- approved specification and drawings;
- approved or “golden” sample details;
- bill of materials or critical component list where appropriate;
- color, finish, and workmanship limits;
- packaging artwork and barcode data;
- destination-market labeling requirements;
- inspection checklist and test methods;
- sampling plan and acceptance decision rules;
- known defects from samples or earlier orders;
- carton count and packing list.
Avoid instructions such as “check quality is good.” Every important check needs an observable characteristic and limit.
Verify lot identity and quantity
The inspector should identify the factory, warehouse area, purchase order, model, lot, and total quantity presented. Cartons should be selected across the available lot rather than handed to the inspector by factory staff.
Reconcile finished units, incomplete units, rejected goods, packed cartons, and any shortfall. Check carton numbering and packing-list arithmetic. A quality result on an incomplete or mixed lot may not support release of the actual shipment.
Use sampling intentionally
Many buyers use an acceptance-sampling standard such as ISO 2859-1 or ANSI/ASQ Z1.4 for visual workmanship. The chosen inspection level and acceptance quality limit (AQL) determine the sample size and acceptance numbers.
AQL does not mean a permitted percentage of defective goods in the shipment, and a passed sample does not prove zero defects. It is a statistical lot-acceptance method. Critical safety or regulatory characteristics may require different controls, including 100% checks or laboratory testing.
Define defect categories before inspection:
- Critical: could create an unsafe, unlawful, or fundamentally unusable product.
- Major: likely to cause failure, return, significant dissatisfaction, or inability to sell as intended.
- Minor: deviation from the standard that does not materially impair normal use.
Include defect photographs and boundary samples where words are ambiguous.
Check workmanship and dimensions
Visual inspection should cover surfaces, assembly, alignment, color, printing, cleanliness, odor where relevant, sharp edges, loose parts, and other product-specific defects.
Measure critical dimensions with suitable calibrated equipment. Specify measurement locations and conditions. For textiles, wood, plastics, or other materials affected by conditioning, the method may matter as much as the number.
Record actual measurements, not only “pass.” A table of results helps identify drift even when every sampled unit remains inside tolerance.
Perform function and safety-related checks
Functional checks should reproduce intended use or a defined test method. Examples include assembly, switch operation, load, leak, fit, adhesion, torque, charging, connectivity, or repeated cycles.
Safety and compliance checks depend on the product and destination. An on-site inspector may verify markings, components, construction, simple functions, and presence of documentation. They usually cannot replace accredited laboratory testing required for electrical, chemical, flammability, food-contact, or other regulated properties.
Link each test to the approved requirement. Record equipment identification, setup, sample quantity, actual result, and photographs.
Inspect packaging and labeling
Packaging failures can turn conforming products into claims. Check:
- unit, inner, and master-carton configuration;
- protective materials and sealing;
- carton dimensions, gross weight, and strength specification;
- product and model identification;
- country-of-origin marking;
- warnings, instructions, traceability, and compliance marks;
- barcode content, readability, placement, and uniqueness where required;
- assortment and quantity per carton;
- shipping marks and purchase-order references.
Scan barcodes rather than judging them visually. Compare decoded data with the approved file.
For a carton-drop test or packaging test, define the method in advance. An improvised drop from an unknown height produces little comparable evidence.
Record evidence clearly
The report should contain lot information, sampling plan, checklist results, measurements, defect counts by category, test data, and labeled photographs. Photographs should show the inspected lot and carton selection as well as close-ups.
Ask the inspector to distinguish observed facts from supplier explanations. “Supplier promises to repair” does not change the inspection result; it starts a corrective-action process.
Make the release decision outside the factory
The inspection company reports evidence. The buyer should decide whether to:
- release the shipment;
- require sorting or rework and reinspection;
- accept a documented concession;
- hold shipment pending test results;
- reject or renegotiate the lot.
Do not allow the supplier to pressure an inspector into changing classification or sampling. If a deviation is acceptable for commercial reasons, document who approved it, affected quantity, price or warranty treatment, and whether the specification changes for future orders.
If the inspection fails
Require the supplier to identify affected stock, contain it, determine cause, perform corrective action, and provide records of rework or sorting. A reinspection should normally draw a new random sample from the corrected lot.
Review whether the failure reveals a broader control problem: unclear specification, unapproved material, ineffective first-piece approval, poor process control, or inadequate in-process inspection. Fixing only the sampled defects may not prevent recurrence.
Build inspection into the purchase process
Agree before the order who selects the inspection provider, which documents control, when inspection occurs, who pays for initial and repeat inspections, what constitutes readiness, and how payment or shipment release depends on results.
Used this way, a PSI is not a last-minute search for defects. It is a pre-agreed decision gate that converts the buyer’s requirements into observable evidence before the goods leave China.
Continue the sourcing workflow
- Put inspection scope and release conditions into the China purchase order checklist.
- Define sampling decisions with the AQL inspection guide for China orders.
- Protect the approved pack-out with a China packaging specification.
- Preserve the comparison standard through a documented product sample approval process.
Sampling and test requirements should reflect the product’s safety, regulatory, and commercial risks. Seek qualified technical or legal advice where regulated requirements apply.