Once a container leaves the supplier's country, your leverage is gone. You are holding goods you have largely paid for, in a port thousands of kilometres from the factory, with a supplier who now has very little incentive to help.
Pre-shipment inspection exists to move the discovery of a problem to the one moment when it can still be fixed cheaply: while the goods are on the factory floor and the balance of your payment is unpaid.
When to inspect
Pre-production inspection checks raw materials and components before assembly begins. Worth it for high-value or safety-critical goods, or a supplier you have not used before.
During-production inspection happens at roughly 20–50% completion. Its value is time: a systemic defect caught at 30% can be corrected on the remaining 70% rather than reworked across the whole order.
Pre-shipment inspection (PSI) is the standard, and the one most buyers should default to. It happens when production is 100% complete and at least 80% packed. This is the inspection that should gate your final payment.
Container loading supervision confirms that what was inspected is what actually goes into the container, in the right quantity, loaded and secured properly. It is cheap and it closes an obvious substitution gap.
For a first order with a new supplier, PSI is the minimum. Adding loading supervision is usually a modest incremental cost and removes the most common remaining failure.
How inspection sampling works
Inspectors do not check every unit. They use AQL — Acceptable Quality Limit — sampling, defined in ISO 2859-1.
You choose an AQL level per defect class. Conventional defaults for consumer goods:
- Critical defects: 0. Anything unsafe or illegal. No tolerance.
- Major defects: AQL 2.5. Would cause a return or make the item unsaleable.
- Minor defects: AQL 4.0. Cosmetic issues a customer would probably accept.
For an order of 5,000 units at General Inspection Level II, the sample size is 200 units. At AQL 2.5 for major defects, the inspection passes if 10 or fewer major defects are found and fails at 11.
Two things follow that buyers routinely misunderstand:
A "pass" is not a guarantee of zero defects. It is a statistical statement that the defect rate is probably below your chosen threshold. If you need near-zero, you must specify a tighter AQL and pay for a larger sample.
You must set the AQL yourself. If you do not, the inspection company applies its default, which may be looser than your market tolerates.
What to specify before the inspector arrives
An inspection is only as good as the checklist. "Check the goods are OK" produces a report that says the goods are OK.
Provide, in writing:
- The approved sample or reference specification. Ideally the inspector has a golden sample in hand. Photographs and a written spec are the fallback.
- Dimensions and tolerances, with the measuring method.
- Function tests. What must be tested, how many units, and what constitutes a pass. "Charge test at 60W for 30 minutes on 20 units" is testable; "works properly" is not.
- Packaging and labelling requirements, including barcodes, country-of-origin marking, and any market-specific label.
- Quantity verification and carton count.
- Your AQL levels for each defect class.
- Any regulatory marking the destination market requires.
Regulatory inspection is a separate thing
This trips up importers into East and West Africa constantly. Some markets legally require an inspection before shipment, performed by a government-appointed body — and this is not the same as your own commercial quality inspection.
- Kenya operates PVoC (Pre-Export Verification of Conformity). Regulated goods require a Certificate of Conformity issued before shipment by a KEBS-appointed agency. Goods that arrive without one face heavy penalties, and the certificate cannot be issued retroactively.
- Nigeria operates SONCAP for regulated products, with a Product Certificate obtained on the supplier's side feeding the SONCAP Certificate.
- Ghana applies conformity assessment through the Ghana Standards Authority for goods in scope.
- South Africa enforces compulsory specifications via the NRCS.
Your commercial PSI does not satisfy any of these, and a government conformity certificate says nothing about whether the goods match your specification. Regulated shipments need both.
Choosing an inspector
Use a third party that is independent of your supplier. The whole value of the exercise is independence, and an inspector introduced by the factory has an obvious conflict.
The large international firms — SGS, Bureau Veritas, Intertek, TÜV — cost more but carry accreditation and are recognised by banks and insurers. Regional inspection firms are cheaper and often perfectly good for straightforward consumer goods.
Typical cost is a day rate in the region of $250–350 per man-day, with most orders needing one day. Against a $40,000 order, that is well under one percent of value to remove your largest single risk.
Book five to seven days ahead. Inspectors are scheduled, and a supplier who "suddenly" finishes production early and wants to ship immediately is a pattern worth noticing.
When the inspection fails
This is the moment the whole arrangement pays for itself — provided you decided in advance what happens.
Do not release payment. This is why the inspection gates the payment rather than following it. If you have already paid, you are negotiating from nothing.
Get the defect classification and evidence. A good report includes photographs, quantities, and the specific specification clause breached. That evidence is what converts an argument into a claim.
Choose a remedy explicitly. Common outcomes: full rework and re-inspection at the supplier's cost; sorting to remove defective units with the shortfall credited; a negotiated discount if the defect is genuinely minor; or cancellation and refund for a critical failure.
Re-inspect after rework. The re-inspection cost is normally the supplier's, and this should be in your contract. Rework that is not re-inspected is a claim you have chosen to accept on trust.
Know your shipping deadline. Rework takes one to three weeks. If your goods are seasonal, factor the delay into whether you accept a discount instead — that decision is commercial, not technical, and it is yours rather than the inspector's.
The economics
Buyers resist inspection because it feels like paying for something that produces nothing. The correct comparison is not inspection cost against zero — it is inspection cost against the cost of discovering the same defect at the destination port.
At that point you are holding paid-for goods, accruing demurrage, facing return freight that frequently exceeds the value of the goods, and negotiating with a supplier who has your money. A few hundred dollars spent while the goods are still on the factory floor is the cheapest insurance in the entire import process.