Scientific collaboration networks. II. Shortest paths, weighted networks, and centrality - art. no. 016132

Using computer databases of scientific papers in physics, biomedical resear ch, and computer science, we have constructed networks of collaboration bet ween scientists in each of these disciplines. In these networks two scienti sts are considered connected if they have coauthored one or more papers tog ether. Here we study a variety of nonlocal statistics for these networks, s uch as typical distances between scientists through the network, and measur es of centrality such as closeness and betweenness. We further argue that s imple networks such as these cannot capture variation in the strength of co llaborative ties and propose a measure of collaboration strength based on t he number of papers coauthored by pairs of scientists, and the number of ot her scientists with whom they coauthored those papers.