The concordance and strict concordance probabilities are introduced here in order to compare the results of two dosing instruments. These probabilities represent the concordance of the two instruments with regards to the ordering of a set of biological samples taking into account an equivalence margin. They are especially interesting in a screening context in research where the primary requirement is to obtain the same hierarchy between different samples rather than obtaining precisely the same values. A method to test whether a new dosing instrument can reproduce the results of a reference one according to these measures is also presented and illustrated by means of an example.

concordance probability, method validation.