Non-parametric criterion for estimation of the sensitivity of object´s features to influences of a factor and its application in clinical practice

A non-parametric criterion is proposed for estimation of the ability of indicators to reflect changes in an object influenced by a factor, by comparing results of two studies in two tests. The generic properties of the L² indicator are determined using its relation to a non-parametric sign criterion. The range of values of the indicator is [0, 1]: A) the indicator takes a value of 0 if the two studies show no difference in the distribution of the sign differences between the values of the indicator in both tests; B) the indicator becomes 1 in case of inversion in the number of positive and negative differences between the values of the indicator in the two tests in both studies. An example of the indicator´s application is presented in an electrocardiological study.