Metrologien

Metrology, the science of measurement, encompasses theory, methods, and practice for defining, realizing, and applying measurement units. It seeks to ensure that measurements are accurate, reliable, and comparable across time and space. In German-language contexts, the field is also referred to as Metrologie, with the plural Metrologien. Metrology is commonly divided into three domains: scientific metrology (the development of measurement definitions and measurement science); industrial metrology (maintenance of measurement infrastructure and quality control in manufacturing); and legal metrology (ensuring fair trade and safety through measurement regulations).

At the heart of metrology are units and traceability: measurement results are linked to internationally agreed standards through a chain of calibrations. The International System of Units (SI) provides the base for most measurements. National metrology institutes (NMIs) such as PTB, NIST, and others maintain reference standards and provide calibration services. The Bureau International des Poids et Mesures (BIPM) coordinates international standards, while the CIPM oversees the system. Uncertainty evaluation, as formalized in the Guide to the Expression of Uncertainty in Measurement (GUM), expresses the doubt in any measurement result.

Metrology underpins science, industry, health, and commerce, enabling traceable, reproducible results and fair trade. It also involves legal metrology agencies that regulate measuring instruments used by the public, such as scales, gas pumps, and safety devices. Ongoing developments include redefinitions of SI units in terms of fundamental constants and advances in measurement science, instrument technology, and data analysis.