Quality Control Inspection

‘AQL ‘stands for ‘Acceptance Quality Limit ‘, and is defined as the “quality level that is the worst tolerable” in ISO 2859-1. It represents the maximum number of defective units, beyond which a batch is rejected. Importers usually set different AQLs for critical, major, and minor defects. Most Asian exporters are familiar with this type of setting. qualityinspection.org

In practice, three types of defects are often distinguished. For most consumer goods, the limits are

  • -0% for critical defects (totally unacceptable: a user might get harmed, or regulations are not respected).
  • -2.5% for major defects (these products would usually not be considered acceptable by the end user).
  • -4.0% for minor defects (there is some departure from specifications, but most users would not mind it).

If you ordered different products, consider each product as a separate lot. (The quantity of each product is the lot size). If you ordered only one product, the lot size is the total batch quantity.

Different inspection levels will command different numbers of samples to inspect, for the effects of this exemplification we are using Level II

To follow this example, let’s assume your lot size is composed between 10,000 to 35,000 pieces, and based on the inspection level agreed upon is level II, meaning that your code letter is “M”.


Our code letter is “M”, so we would need to pick up a badge of 315 pieces out of the total lot; assuming you´ve established an AQL at 2.5% for major defects, and 4.0% for minor defects, so based upon this metrics, no more than 10 products with MAJOR defects will be allowed and no more than 14 products with MINOR defects will be accepted.

For example, if 15 products with MINOR defects were found, and 11 of them with MAJOR defects were detected, the products are rejected, but if we find 12 pieces with MINOR defects and only 7 pieces with MAJOR defects, then the lot is accepted.

Other criteria usually employed when conducting a QCI are:

  • Packaging conformity (barcodes, inner packing, cartons, shipping marks, logos…).
  • Product conformity (aspect, workmanship…). If all the products are in red color instead of orange, there is no need to count each sample as a defect. It makes more sense to refuse for product conformity.
  • Specific tests defined in the inspection checklist (they might not be performed on all inspected samples if they are time-consuming or destructive).