Comparison of different ways of measuring the clustering coefficient and degree assortativity.

represents the global clustering coefficient; , the mean local clustering coefficient; r, degree assortativity (the correlation coefficient of degree); and r log, the correlation coefficient of the log of degree. To eliminate the effects of hyper-authorship, subsets labeled include authors with degree (d) no more than 100 and papers (n) with no more than 50 authors. Subsets labeled “all” exclude nothing.