The analytical data received in an inter‐laboratory study of four Canadian reference samples were treated by two different methods in order to arrive at “usable values” for the concentration of each constituent. The first method (“Select Laboratories”), proposed by S. Abbey (S.A.), is based on the fact that some laboratories consistently produce better results than others. S.A. suggests an approach which permits isolation of results from such laboratories, calculation of a mean or a median of such results and use of one or the other as the concentration of a constituent. That approach involves a degree of subjectivity and S.A. attempts to demonstrate the validity of his approach by means of several tests applied to the results obtained for the fou