The assortative index (A. Index) of a real-world network with respect to a centrality metric is computed as the Pearson’s correlation coefficient of the centrality values of the end vertices of the edges. The Pearson’s product-moment correlation coefficient between two sets of vertices X and Y (whose entries represent the centrality values for one or more vertices with respect to a particular metric C) is calculated as follows. The jth element in the sets X and Y is denoted by xj and yj respectively. Let and (calculated as in formulation-1 below) be respectively the average values for the centrality metric of interest (C) among the vertices constituting the sets X and Y.