posted 15 September 2000 03:58 PM               

-----------------

Edited html to make active link.

posted 15 September 2000 04:43 PM               

I learn like you do. All I can say is I have not fould one 'simple' article. I think I can explain it, but I don't have to do the calculations and such so I have no hands-on experience in determining uncertainty per se. However - you do have to look at what uncertainty is - for example, in an R&R, what is uncertainty? In Gage R&R it's the confidence limits. You buy a thermometer and the instructions say it's accurate to +/-2 degrees - your uncertainty is 4 degrees (as I understand it). When you get to an uncertainty budget, it's the combination of all uncertainties of the entire system.

posted 29 September 2000 08:50 AM              

Here are a few publications I have found useful. I have tried to list them in order of increasing difficulty.
"An Introduction to Error Analysis" by John R. Taylor (second edition, University Science Books, Susalito CA: 1997. ISBN 0-935702-75-X) This is an excellent book that starts off easy and gradually works into more difficult areas.
"Calibration: Philosophy in Practice" by Fluke Corporation (second edition, Fluke Corporation, Everett WA: 1994. ISBN 0-9638650-0-5) Although geared to electrical/electronic measurements, the principles are usable in every measurement area. Chapter 22 is about uncertainty statements, but first you will need to read either chapters 20 & 21, or the book by Taylor.
"Determining and Reporting Measurement Uncertainties", National Conference of Standards Laboratories Recommended Practice # RP-12. (NCSL, Boulder, CO: 1995) Somewhat easier to understand than the ISO standard (next), but still very technical. This includes a few practical examples writtem by metrology managers.
ANSI/NCSL Z540-2, "American National Standard for Expressing Uncertainty -- U.S. Guide to the Expression of Uncertainty in Measurement". (NCSL, Boulder, CO: 1997) This is the official US adoption of the ISO guide: very technical, but the authoritative standard.

The NCSL publications are available from the organization (www.ncsl-hq.org). The Fluke book is available from your Fluke sales representative. The Taylor book can be ordered through any major online or traditional book retailer.

Please feel free to contact me directly for additional information.

Graeme C. Payne
ASQ Certified Quality Engineer
[email protected]