JCGMohjeistukset

JCGMohjeistukset, also known as the Guide to the Expression of Uncertainty in Measurement (GUM), is a fundamental document in the field of metrology. Published by the Joint Committee for Guides in Metrology (JCGM), it provides a comprehensive framework for evaluating and expressing uncertainty in measurement. The GUM is widely recognized and adopted internationally, serving as a cornerstone for ensuring the reliability and comparability of measurement results.

The GUM outlines a systematic approach to uncertainty analysis, emphasizing the importance of quantifying all sources of uncertainty that can affect a measurement result. It introduces the concept of a "standard uncertainty," which is the uncertainty of a measurement result expressed as a standard deviation. The GUM also defines the "combined standard uncertainty," which is the square root of the sum of the squares of the individual standard uncertainties, assuming they are independent.

One of the key features of the GUM is its emphasis on a probabilistic approach to uncertainty. It recommends using statistical methods to estimate uncertainties and provides guidelines for applying these methods to different types of measurements. The GUM also addresses the issue of correlation between uncertainties, which can significantly impact the overall uncertainty of a measurement result.

The GUM is not limited to simple measurements; it also provides guidance for more complex scenarios, such as those involving calibration, interlaboratory comparisons, and the use of reference materials. It encourages practitioners to document their uncertainty analysis processes to ensure transparency and reproducibility.

The GUM has been updated and revised several times to keep pace with advancements in measurement technology and statistical methods. The most recent version, published in 2008, is known as the GUM Supplement 1, which includes additional guidance on specific topics such as the use of Monte Carlo methods for uncertainty evaluation.

In summary, JCGMohjeistukset, or the GUM, is an essential resource for anyone involved in measurement science. It provides a standardized approach to uncertainty analysis, ensuring that measurement results are reliable, comparable, and traceable to international standards.