Table 1. Basic statistics of the data sets.

N is the number of individuals; M is the number of links. x is the connectance (fraction of vertex pairs that are links). C is the clustering coefficient of the original network and C′ denotes the averaged values of random graphs with the same expected degree sequence as the original network [36].

Data set	N	M	x	C	C’
HIV	40	41	0.052	0.034	0.094
Colorado Springs	324	345	0.004	0.026	0.029
Iceland	75	114	0.041	0.16	0.20
Prostitution	16,730	39,044	0.0002	0	0.010
Conference	113	2,196	0.34	0.50	0.48
Hospital	75	1,139	0.41	0.58	0.57
School 1	236	5,901	0.21	0.43	0.28
School 2	238	5,541	0.20	0.47	0.27