Estimation of measurement bias using several methods.

The accuracy of a measurement method is all the better when we have a true value for the quantity being measured. But what is true value? Is it not a holy grail, a mythical notion that is the object of a scientific quest that brings together lab assistants around a bench?

Although this true value is not known with certainty, it is possible to have an accepted reference value, by means of :

• reference materials ;

• preparation of a known sample ;

• a reference measurement method of recognized accuracy ;

• interlaboratory tests.