Therefore, the department isn't looking to compare the discrimination ability of one OC curve to another, nor is it using AOZ plans to economize on sample size. Use of AOZ plans for some contracts will result in excessive lot rejection. Lots with nonconformances in the sample are candidates for a normal part of business, namely, negotiations between the consumer and the supplier based on waiving the contractual requirements for concessions that have balanced value to both. Process control The Defense Department's goal is for its contractors to control their processes so well, and with such a high capability, that lot acceptance via AOZ plans becomes unnecessary. Keep in mind that the normal contract requires totally conforming product.
Samples are just one form of objective evidence.
Compared with the information given by other techniques, like SPC charts or error-proofing, samples make for a fairly weak set of evidence. However, AOZ plans will be the criterion for final lot acceptance as long as contractors have processes that aren't mature enough to generate better objective evidence. How long it takes to make the necessary improvements is the supplier's own choice. When AOZ plans stand alone, higher quality levels are achieved only because of the supplier's fear of excessive lot rejection. The big picture is that process controls are needed to stabilize, monitor and improve processes.