Pre-shipment inspection explained: AQL sampling, what to check, and how to use the report

Once goods leave the supplier's factory and you've paid in full, fixing a quality problem becomes slow, expensive and sometimes impossible. A pre-shipment inspection (PSI) checks the goods while they're still at the factory, so problems can be fixed before shipment and before final payment.

This guide explains how inspections work, what AQL means, and how to use the inspection report.

Types of inspection

Inspections can happen at several stages of production:

• Pre-production inspection: checks raw materials and components before production starts.
• During production inspection (DUPRO): checks early production, usually when 10 to 30% of the order is made, to catch problems while they can still be corrected.
• Pre-shipment inspection (PSI): checks finished goods when production is complete and most of the order (typically at least 80%) is packed. This is the most common inspection.
• Container loading check (CLC): supervises loading to confirm the right goods, quantities and packing go into the container, and records the container and seal numbers.

For new suppliers or large orders, combining DUPRO and PSI is a good investment.

What is AQL?

You usually can't inspect every unit in an order. Inspectors check a random sample, and the Acceptance Quality Limit (AQL) decides whether the whole lot passes or fails based on how many defects are found in that sample.

AQL sampling is defined in ISO 2859-1 (equivalent to the older ANSI/ASQ Z1.4 and MIL-STD-105E standards). It uses:

• Lot size: the number of units in the order.
• Inspection level: how strict the sampling is. General Level II is the most common.
• From these, a table gives the sample size, the number of units to inspect.
• The AQL value for each defect category gives the maximum number of defects allowed in that sample.

Defect categories

• Critical defects: could cause harm or break safety regulations. Most buyers set AQL 0, meaning none are allowed.
• Major defects: likely to cause product failure or returns, or make the product unsaleable. Commonly AQL 2.5 for consumer goods.
• Minor defects: small deviations unlikely to affect function or sales. Commonly AQL 4.0.

For example, for a lot of a few thousand units at General Level II, the table might call for a sample of a couple of hundred units, with a set number of major and minor defects allowed. If the defects found exceed those numbers, the lot fails.

The values are a business decision: stricter AQLs mean higher quality and higher cost. Agree them with the supplier before production starts and write them in the purchase order.

What inspectors check

A typical pre-shipment inspection covers:

1. Quantity: the number of units produced and packed against the order.
2. Packing and marking: export cartons, shipping marks, labels, barcodes, inner packing.
3. Visual appearance: workmanship defects such as scratches, stains, loose threads, colour differences.
4. Dimensions and weight: measured against the specification.
5. Function and performance tests: the product works as intended.
6. Specific tests: such as drop tests for cartons, colour fastness for textiles, electrical safety tests for appliances, or moisture checks for agricultural products.
7. Comparison with the approved sample (the "golden sample").

Preparing for an inspection

As a buyer:

• Provide the inspector with a clear specification: drawings, materials, colours, tolerances, approved samples and packing instructions.
• Define what counts as critical, major and minor defects for your product.
• Agree the AQL levels and any special tests.
• Tell the supplier the inspection date and make sure goods will be ready.

As a supplier:

• Have goods finished and mostly packed on the agreed date.
• Provide space, lighting, testing equipment and staff to open cartons.
• Do your own internal quality check first; a failed inspection usually means re-inspection costs and delays.

Reading the report

The report usually includes:

• result: pass, fail or pending (when the buyer must decide)
• sample size and defects found in each category
• photos of defects, packing, labels and measurements
• results of tests performed
• comments from the inspector

If the result is a fail, the usual options are: the supplier reworks or sorts the goods and a re-inspection is done; the buyer accepts the goods with a price reduction; or the shipment is rejected. Agree in your contract who pays for re-inspections.

Linking inspection to payment

A common structure is a deposit with the order and the balance payable only after a passed inspection. Under a letter of credit, you can require an inspection certificate from a named agency as one of the documents for payment. See our guide to export payment methods.

Who does inspections

Inspections are done by independent inspection companies, including large international firms and many regional agencies, or by your own quality staff. Choose an agency with experience in your product category and inspectors near the factory. For regulated products, some countries require inspection by specific approved agencies.

Frequently asked questions

What does AQL 2.5 mean?

It sets the maximum number of defects allowed in the inspected sample for that defect category, using the ISO 2859-1 tables. AQL 2.5 is a common level for major defects in consumer goods.

Who pays for inspection?

Usually the buyer pays for the first inspection, and the contract often says the supplier pays for re-inspections after a failed result. Agree this before production.

When should the pre-shipment inspection happen?

When production is complete and most of the order, typically at least 80%, is packed, so the inspector can draw a representative sample.

Is a pre-shipment inspection enough for new suppliers?

For new suppliers or large orders, add a during-production inspection so problems are caught while they can still be fixed.

Find reliable suppliers on GlobalMart

Inspection works best with good suppliers. Compare manufacturers on GlobalMart's supplier directory, read our guide on how to verify a supplier, and post your requirement with your quality and inspection requirements stated up front.