Uncertainty of Measurement
ISO/IEC 17025: 2005
By Dr. Donald Orokos
Measurement is essential to testing, calibration and research laboratories because scientists can include quantitative data with their results or findings. However, when a measurement is made the value of the measurement is not absolute—one can assume that there will be some type of “error or uncertainty” in that measurement. Today, estimating uncertainty of measurement is a key procedure required by all laboratories seeking ISO17025 accreditation. Laboratories that practice measurement of uncertainty demonstrate to their customers’ good laboratory practice and a certain level of confidence in their reported quantitative results.
This two hour presentation on estimating uncertainty of measurement is aimed at all scientists, supervisors, and administrators currently working in a testing or calibration laboratory seeking ISO17025 accreditation. More importantly, this presentation is also for those individuals who are involved, or will be involved in the estimation and reporting uncertainties of measurement.
The overall goal of this two-hour PowerPoint presentation is to provide participants with a general understanding of the concepts and terminology used for estimating uncertainty of measurement. Time will be spent on discussing the steps of estimating and reporting uncertainties through a combination of lecture and interactive examples and problems.
Some of the topics covered in this presentation will include:
- What is Uncertainty?
- Components of Uncertainty: Random and Systematic
- Steps Estimating the Uncertainty of Measurement
- Basic Statistical Concepts
- Type A or B Evaluations of Uncertainty
- Quantify Uncertainty based on Type/Formula
- An Uncertainty Budget
- Combined Uncertainty
- Expanded Uncertainty
- An Uncertainty Report