Acceptance quality limit (AQL)

Acceptance quality limit, AQL, is a parameter used to select acceptance-sampling plans for a series of lots. Current ISO guidance describes AQL-indexed inspection schemes and uses Acceptance Quality Limit; the older name Acceptable Quality Level remains in use.[2] AQL does not guarantee the exact defect proportion in every accepted lot.[1]

Specify inspection level, defect classes, sampling and decision rules as well as AQL. Acceptance is probabilistic: a good lot can be rejected and a poor lot accepted.[1] A sampling outcome therefore does not individually approve every unit delivered.