ISO 5725-4:2020

1.1  This document
-  specifies basic methods for estimating the bias of a measurement method and the laboratory bias when a measurement method is applied;
-  provides a practical approach of a basic method for routine use in estimating the bias of measurement methods and laboratory bias;
-  provides a brief guidance to all personnel concerned with designing, performing or analysing the results of the measurements for estimating bias.
1.2  It is concerned exclusively with measurement methods which yield measurements on a continuous scale and give a single value as the measurement result, although the single value can be the outcome of a calculation from a set of observations.
1.3  This document applies when the measurement method has been standardized and all measurements are carried out according to that measurement method.
NOTE    In ISO/IEC Guide 99:2007(VIM), "measurement procedure" (2.6) is an analogous term related to the term "measurement method" used in this document.
1.4  This document applies only if an accepted reference value can be established to substitute the true value by using the value, for example:
-  of a suitable reference material;
-  of a suitable measurement standard;
-  referring to a suitable measurement method;
-  of a suitable prepared known sample.
1.5  This document applies only to the cases where it is sufficient to estimate bias on one property at a time. It is not applicable if the bias in the measurement of one property is affected by the level of any other property (i.e. it does not consider interferences by any influencing quantity). Comparison of the trueness of two-measurement methods is considered in ISO 5725-6.