A paper on selecting sampling AQLs is available in the Ombu Library

This paper, prepared for Ombu customers, describes two aspects of selecting an AQL for attribute sampling plans.

The AQL is the “worst case” process average you, as the customer, are willing to accept from your supplier. The supplier could be either internal or external.

The AQL is also a point on the Operating Characteristic (OC) curve. The OC defines the long term probability of accepting lots from various process averages. Traditionally, the AQL is the point with a process average that has a 95% probability of acceptance.