- acceptance sampling
- zero acceptance
The zero acceptance number plans developed by the author were originally designed and used to provide equal or greater consumer protection with less overall inspection than the corresponding MIL-STD-105-E sampling plans. In 2000, the Department of Defense declared MIL-STD-105-E obsolete and recommended the c=0 plans in this book for use in place of them. In addition to the economic advantages, the plans in this book are also simple to use and administer.
Copies printed after 2011 include the most up-to-date sampling plans.
For questions about c0 sampling table, see the explanation below:.
Zero Acceptance Number (c=0) Sampling Plans Fifth edition by Nicholas L. Squeglia
Further explanation on Sampling Plan changes from the fourth edition
In the previous editions, it was noted that there were several cases where downward adjustments were made in sample sizes to compensate for anomalies in the Mil plans in order to have a smooth progression. For example, page 16 of the fourth edition noted that higher LQ's were allowed than the corresponding Mil plans. The users were given the option of using the higher sample sizes if they had an aversion to the downward adjustment.
In the fifth edition, as mentioned on page 12, essentially these sample sizes were increased to closely meet the targeted Mil LQ's. The decision was influenced by a large aerospace company having some 2000 suppliers that opted to go with the higher sample sizes to meet the targeted LQ's. In order to compensate for the anomalies in the Mil plans and to still have a smooth progression in the fifth edition, these cases have higher sample sizes than the Mil plans.
The cases that now have sample sizes greater than the Mil plans are:
- Lot size 2-8, Index 6.5, increase of 1 Also, results in an increase of 1 from fourth edition
- Lot size 9-15 Index 6.5, increase of 1, Also, results in an increase of 1 from fourth edition
- Lot size 26-50 Index 2.5 increase of 2, Also results in an increase of 2 from fourth edition
- Lot size 51-90 Index 1.5 increase of 5, Also results in an increase of 5 from fourth edition.
- Lot size 91-150 Index 1.0 increase of 6, Also results in an increase of 6 from fourth edition
- Lot size 151-280 Index .65 increases of 9, Also results in an increase of 9 over fourth edition.
The affected sample size increases from the fourth edition (still are smaller than the Mil plans) are:
- Lot size 2-8, Index 10.0 results in an increase of 1
- Lot size 9-15, Index 10.0 results in an increase of 1
- Lot size 16-25, Index 10.0 results in an increase of 1
- Lot size 26-50, Index 4.0 results in an increase of 2
- Lot size 51-90 Indexes 2.5 and 4.0, increases of 4, and 2 respectively
- Lot size 91-150 Indexes 1.5 and 4.0, increases of 7, and 2
- Lot size 151-280, Index of 1.0, results in an increase of 9.
Unless specified by contract, or otherwise, the c=0 plans are flexible and the fourth edition table can be used if this better suits your needs. Table 1 in the fifth edition is noted as the "fifth edition" in the lower right hand corner. Previous editions do not refer to the edition in the table. In addition to the c=0 plans being statistically valid, the c=0 plans book goes a step further and provides justification where the user may use sampling plans that are not statistically valid. Not being AQL plans, considerations as mentioned in the book help determine the choice of index levels and other means for further reducing your inspection costs, such as audit samples, process controls, etc. Index levels should be reviewed periodically.
- Nicholas Squeglia