You are here:

Measurement Uncertainty

Background

The purpose of this Working Group is to exchange experiences on methods for assessment of measurement uncertainties, of monitoring measurement processes, and promoting the consideration of measurement uncertainty in industrial and business applications of statistical methods.

This is a field traditionally involving scientists from chemistry, physics, biochemistry and other related sciences, but it must be considered also an area of increasing interest to statisticians as well.

A number of guidelines and standards exist within this area. Among the most important ones are "Guide to the expression of uncertainty in measurement" (GUM) and ISO 5725 (1-6) "Accuracy (trueness and precision) of measurement results".

The GUM uses the "bottom up" approach (deductive), i.e. constructing "uncertainty budgets" with estimates of each source of error. These estimates can be either "Type A" (estimates from data) or "Type B" (use of other existing knowledge).

ISO 5725 (1-6) uses the "top-down" approach (inductive), i.e. experimental determination of the accuracy of a standardised measurement method by calculating measures of "repeatability", "reproducibility" and "intermediate precision".

Currently work is going on in ISO (TC69) on integrating the two approaches. A draft version (January 2002) of the document "ISO/DTS 21748: Guide to the use of repeatability, reproducibility and trueness estimates in measurement uncertainty estimation" exists.

An important topic for this working group will be to exchange experiences from both approaches, facilitate integration of the two approaches and promote the consideration of measurement uncertainty in industrial and business applications of statistical methods.

Meeting in Rimini

At the meeting Sep. 24th 2002 in Rimini the following people were present:

Birger Stjernholm Madsen
Kaj Heydorn
Raffaello Levi
Didier Jeannel

The following people were not presented, but have expressed interest in the topic of measurement uncertainty:

Maria F. Ramalhoto
Marion Chatfield

Topics

The following topics were listed, that could be important to discuss in future (non-prioritised order): - Verification of uncertainty budgets
- QA/QC use of uncertainty budgets
- Measurement uncertainty in health services
- CMM: Coordinate Measuring Machines
- Measurement uncertainty and specifications
- Measurement uncertainty and sampling inspection
- The role of measurement uncertainty in six sigma

At present the group considers itself an interest group more than a working group, i.e. it is our hope that the group can play as a network within the ENBIS network!

It is expected, that measurement uncertainty will play in increasing role at future ENBIS conferences. Meanwhile, we hope to be able to benefit from mutually contacting each other with exchanging relevant references, suggesting presentations for next ENBIS conference etc.