Table 2. Statistical data about authors in the co-authorship network.

	Mean	SD	Median	Max
Connected countries	1.2	0.6	1.0	5.0
Connected institutes	6.2	5.5	4.5	38.0
Average h index of co-authors	20.3	13.5	17.5	72.0
Average number of papers of co-authors	6.9	3.5	6.3	21.5
Total Network connections	8.4	6.2	7.0	45.0
Connections per paper	2.1	1.2	1.8	9.5
Second order connections	29.2	30.4	16.0	163.0
Second order connections per paper	7.1	7.3	4.5	62.0
Third order connections	68.3	65.9	3.0	9.0
Third order connections per paper	17.0	19.9	0.6	3.0
Betweenness	3.3	14.5	0.0	228.2
Closeness	2.7	0.9	3.5	3.5

Each row contains one of the “network involvement factors” used to predict author impact. “Betweenness” and “Closeness” are standard measures of node centrality in network theory [22, 23]. Connections refer to the number of authors a given author is connected to in the network.