National Physical Laboratory

Research

Measurement Uncertainties - Methods

All measurements are subject to uncertainty and a measurement is only complete if it is accompanied by an appropriate statement of its associated uncertainty.

Introduction

In many cases quantifying the measurement uncertainty and expressing it in a valid form are not straightforward tasks. Extensive metrological, mathematical and statistical knowledge may be needed to obtain high quality results on which you, your customers and regulatory organisations can rely.

What We Do

NPL's Mathematics & Scientific Computing group has a highly experienced team of technical experts with unparalleled knowledge of uncertainty evaluation. We are part of a world-class physical metrology organisation, and we believe our experience and expertise in this field is unique in the UK. Our work is consistent with internationally recognised advice on best practice in uncertainty evaluation, such as the Guide to the Expression of Uncertainty in Measurement (GUM), published by ISO. Our team is playing a leading international role in the development of supplemental guides to the GUM.

We offer a wide range of services to help you solve your measurement problems, including:

Background Material

Measurement Uncertainties research

  • Electrical Quantum Standards - Overview

    NPL is the UK’s centre for precise electrical measurement. All electrical measurements at frequencies below 10 MHz are traceable to our two primary standards, the Quantum Hall effect resistance, and the Josephson volt.
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  • Propagation of Distributions

    The propagation of distributions offers a more general capability than the law of propagation of uncertainty. It is relevant when the conditions for that law to apply do not hold or when there is doubt over whether they hold.
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