Metrology

Metrology is a scientific study of measurement. The act of Measuring always involves a measuring instrument. Measurement always have errors and uncertainties. A core concept of Metrology is traceability defined as the property of result of a measurement or the value of a standard whereby it can be related to stated references usually national or international standards,through an unbroken chain of comparison all having stated uncertainties. The level of traceability establishes the level of comparibilty of the measurement whether the result of a mesurement can be compared to the previous one, a measurement result a year ago or to the result of a measurement performed anywhere else in the world. The traceability is most often obtained by calibration, establishing the relation between the indication of a mesuring instrument and the value of measurement standard. These Standard are usually coordinated by national laboratories e.g. like National Institute of Standards and Technology(USA)