Lot tolerance percent defective, the defect level at which a plan accepts lots only rarely, usually 10 percent of the time; that 10 percent is the consumer's risk. It is also called the rejectable quality level (RQL) or limiting quality. Semiconductor reliability qualifications use LTPD plans directly: 77 units with zero failures demonstrate an LTPD of 3 percent at 90 percent confidence.
Qual plan is 3 lots of 77 at zero fails, which demonstrates an LTPD of 1 percent at 90 percent confidence.
Also heard as
- lot tolerance percent defective
- RQL
- rejectable quality level
- limiting quality
Related terms
AQL
Acceptable quality level: the defect rate a sampling plan is built to pass most of the time, the good end of its OC curve.
Operating characteristic curve
Graph of a sampling plan's probability of accepting a lot against the lot's true defect rate.
Acceptance sampling
Accepting or rejecting a whole lot based on inspecting a random sample from it against a predefined plan.
Burn-in
Operating products under raised stress before shipment so weak units fail in the factory instead of in the field.