What is LTPD?

Six Sigma – iSixSigma Forums Old Forums General What is LTPD?

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
  • #27137

    Penny Lenaerts


    Can you give me a definition for LTPD?

    Thank you,



    Go get a copy of Juran’s Quality Control Handbook. LTPD is in there as well as how to construct an OC so that you relly know what you have. A copy of any version of MIL-STD-105 will also have this.


    Ken Myers


    As you are out in Europe you may not have direct access
    to Juran’s Handbook as suggested by Gary. I will not
    go into great detail about the concepts of acceptance
    sampling. However, the term LTPD as stated earlier
    stands for “Lot Tolerance Percent Defective”. When
    conducting acceptance sampling the LTPD for a given
    sampling plan is the lot defective level that has
    a 10% chance of acceptance. Put another way, the LTPD
    is the defective level that has a 90% chance of being
    rejected by the sampling plan. Additional details on this topic can be found in many references on the topic of acceptance sampling.

    You might want to look at this site for additional info:


    The author at the site above speaks of the Consumer’s point on the O-C Curve in his explanation. The LTPD is located near this point. Another reference term for LTPD is RQL0.10, or the Rejectable Quality Level at the 10% probability of acceptance.

    Remember, acceptance sampling is not a major theme
    in the Six Sigma method. In acceptance sampling you are first making the lots of product, then trying to remove the bad lots from the good lots. This is an approach that incurs considerable costs. Using the Six Sigma approach you find the causes of producing bad lots of product and remove the causes from the system.

    I hope this helps!

    Good Luck,



    Neil Polhemus

    Following up on the other responses, I like to define the LTPD as the poorest level of quality that a consumer is willing to tolerate in any lot. In constructing many acceptance sampling plans, you specify the LTPD and the consumer’s risk of accepting a lot with that level of quality (often a 10% risk, but not necessarily). When you create an acceptance plan in STATGRAPHICS Plus, you define both the LTPD and the AQL, the latter being the Acceptable Quality Level at which the producer’s risk is set.

Viewing 4 posts - 1 through 4 (of 4 total)

The forum ‘General’ is closed to new topics and replies.