AQL Terms

Pre-shipment Inspections, Factory Audit

Common quality control and inspection terms, in plain language.

TermMeaning
AQL (Acceptable Quality Limit)The worst average defect level you are willing to accept in a lot. A lower AQL is stricter.
Lot (batch)The total quantity being inspected, such as one PO or one style.
Sample sizeThe number of pieces inspected from the lot, set by lot size and inspection level.
Inspection levelGeneral I, II, III (visual checks) or special S1 to S4 (measurements and tests). It changes the sample size.
Critical defectA defect that is unsafe or illegal for the user. Usually AQL 0, no tolerance.
Major defectA defect that makes the product unusable or likely to be returned. Common AQL 2.5.
Minor defectA small deviation that does not affect use. Common AQL 4.0.
Acceptance number (Ac)Maximum defects allowed in the sample for the lot to pass.
Rejection number (Re)The number of defects at which the lot fails.
Normal inspectionThe standard plan used when quality is average.
Tightened inspectionA stricter plan used after repeated failures.
Reduced inspectionA lighter plan allowed after consistent good results.
Sample size code letterThe letter (A to R) linking lot size and level to a sample size.
Random samplingPicking pieces and cartons without bias so the sample represents the lot.
Defective unitA piece with one or more defects.
Pre-shipment inspection (PSI)Final random inspection when goods are packed and ready to ship.
DUPRO / inline inspectionInspection while production is running.
Golden sampleThe approved sample that production must match.
Tech packThe document with the product specifications, measurements and materials.
Packing listThe list of styles, colours, sizes, quantities and cartons in a shipment.
ToleranceThe allowed difference from a specified measurement.
Shade variationA visible colour difference between pieces or panels.
Corrective action (CAPA)Steps the factory takes to fix a defect and stop it recurring.
Points per 100 sq ydThe result of 4 point fabric inspection used to grade fabric rolls.