Lot Tolerance Percent Defective (LTPD): The upper limit on the percentage of defects that a consumer is willing to accept.

Consumers Risk: The probability that a lot containing defects exceeding the LTPD will be accepted.

Producers Risk: The probability that a lot containing the AQL will be rejected.

Operating characteristics curve (OC): The ability of a sampling plan to discriminate between lots of high and low quality is described by it’s operating characteristics curve. The steeper the slope of the OC curve the more discriminating the sampling plan. It can be made steeper by increasing the number of samples to be tested or reducing the number of rejects acceptable.