Subject: Uncertainty in Cal and Testing RE38 Date: Wed, 3 Mar 1999 10:09:02 -0500 (EST) From: Lynn Bradley To: Greg Gogates I'm glad to hear someone else admit lack of comprehension. not 3 minutes before i opened this message, i forwarded a previous iso25 message to a more senior and higher-degreed "lab" pal, asking "is this debate about angels on pin-heads or does it occasionally have substance? ... either it's ethereal or i'm woefully ill-equipped to comprehend..." part of me understands the discussion, but most of me cannot fathom the depths to which it extends. i'll keep reading, learning what i can.... At 04:48 PM 3/2/99 -0500, you wrote: >Date: Tue, 2 Mar 1999 15:18:11 -0500 >From: Peter Pantazopoulos >To: Greg Gogates >Subject: Re: Uncertainty in Cal and Testing RE22 > >I have been following the uncertainty discussion with interest and I must >admit... a lack of comprehension. >I am past my experience here and hope someone can shed light on this issue >for me. > >I am the quality manager of a chemistry "testing" laboratory. >One of the main services to our clients is reliable information. >By this I mean that we analyze a commodity and tell them that there is X >amount of this substance in this commodity. > >But... before we do this... we provide corresponding evidence about the >"uncertainty" of this measurement through a "validation" process. Validating >an analytical method is fairly routine to an analytical lab and mandated by >ISO. > >Example: >The reported number is actually "X +- a relative standard deviation of 10%" > >Question 1 >Is "X +- a relative standard deviation of 10%" what is meant by the >uncertainty of measurement? > >Question 2 >Validation takes time, effort and money... is this the uncertainty budget? > >Thank you in advance for answering what may be a simplistic question. > > > >-----Original Message----- >From: Greg Gogates >To: iso25@quality.org >Date: February 18, 1999 14:25 PM >Subject: Uncertainty in Cal and Testing RE22 > Lynn M. Bradley Director of Environmental Health Association of Public Health Laboratories 1211 Connecticut Ave., Suite 608 Washington, DC 20036 202-822-5227, x 207 www.aphl.org FAX: 202-887-5098