Wrong standard deviation calculation in AIAG SPC manual?

[Miner]

Is this only page that lists the standard deviation with the supporting data?

The incorrect value is used on pp 188 and 189 (calculations for Pp and Ppk).

 

[Matt Savage]

I have an update from a Sr. Program Manager, at AIAG.
He confirmed that the correct standard deviation is 0.188657 (which we all knew) and that “An errata sheet may be issued in the future, but is not scheduled for release soon.” He also stated that the “main concern is ensuring the concept is correct, which it is.” @Bromus, thank you for catching the mistake in the AIAG SPC 2nd Edition.

 

[Bromus]

I have an update from a Sr. Program Manager, at AIAG.
He confirmed that the correct standard deviation is 0.188657 (which we all knew) and that “An errata sheet may be issued in the future, but is not scheduled for release soon.” He also stated that the “main concern is ensuring the concept is correct, which it is.” @Bromus, thank you for catching the mistake in the AIAG SPC 2nd Edition.

True, the formula is correct. But again, people use Appendix F to validate their spreadsheets as required by the IATF 16949 standard. One of the validation rules is that for a certain set of input data we will get the same result as in the validation set. And here's the bug. Therefore errata is needed.

 

[Matt Savage]

I completely agree with you. The very definition and purpose of an errata document is to 'correct' an already printed publication. Perhaps someone at AIAG has already started the process of publishing an errata. I am sure if AIAG heard from more than just me, they might move quicker. (hint, hint)