Metrological Standard
International guidance documents establish a unified framework for evaluating and expressing the doubt associated with a measurement result. The reference known as JCG 100 uncertainty provides the mathematical rules for calculating this margin of error in scientific and industrial calibrations. It ensures that measurements performed in different laboratories can be compared directly.
This common language is used by national metrology institutes worldwide.
Evaluation Methodology
Calculations are divided into Type A and Type B evaluations. The JCG 100 uncertainty framework defines Type A evaluations as those based on statistical analysis of series of observations. Type B evaluations rely on non-statistical information such as calibration certificates, manufacturer specifications, and historic data.
Mathematical Treatment
Combining individual components requires using the law of propagation of uncertainty. Standard uncertainties are squared, scaled by sensitivity coefficients, and summed to determine the combined standard uncertainty of the output estimate. An expansion factor is then applied to produce the expanded uncertainty.
Industrial Compliance
Accredited calibration laboratories must document their measurement capabilities using these procedures to maintain their international status. Audits verify that the calculated budgets include all significant sources of error, such as ambient temperature shifts and instrument resolution limits. Having a compliant budget allows a facility to issue certificates that are accepted across borders.
This documentation underpins the global trade of manufactured sensors, which rely on precise tolerance limits.
