AbstractThere is a need for standardization of the mathematical treatment applied to data generated by magnitude estimation techniques in colour scaling, in which hue, saturation [colourjulness]. and absolute or relative brightness are scaled by observers. An aspect of data analysis which has not been considered adequately is the method employed in averaging scaled data points in hue‐saturation space. This article suggests a possible approach: averaging on the assumption of global cylindrical polar coordinates describing hue and saturation, with rectangular Cartesian coordinates assumed for each individual cluster of points to be averaged. The method described here generates concentration ellipses which can be used to give discrimination data in any direction. The question of interobserver normalization is also addressed, as well as that of accuracy limitations of the proposed method.