Tuesday, May 17, 2005

Barry Wellman's Net Lab: Community Central

Last week Connectedness got a mention on SOCNET from Barry Wellman. Barry doesn't get as much press in the business consulting world as some other social network gurus out there, but in the realm of INSNA (the International Network for Social Network Analysis) he is pre-eminent. In fact, Barry founded INSNA.

Barry has an extremely high degree of what is technically refered to as "centrality."* In layman's terms, that means that when Barry says "Connectedness is OK," the result is more traffic in two days than Connectedness had seen in the entire previous month.

In contrast, when I say "Barry Wellman's Net Lab is a fantastic compilation of research on how the Internet affects everday life," chances are that Net Lab's web servers will not strain perceptibly under the additional traffic I refer their way.

Astute readers may be wondering, "Is centrality really the whole story?" That's a good question, and the answer depends in part on how we decide to define "centrality."

The funny thing about centrality is that it is so central to our intuition about social networks and yet it is not easy to pin down with mathematical precision. This is partly due to computational complexity, but mostly I think it's because we're so used to thinking informally about centrality that even after we think we've formalized it, we still forget to verify the sensibility of our equations. That's a message I recently took away from Steve Borgatti's paper "Centrality and network flow," Social Networks Vol. 27, issue 1 (Jan 2005). I'll say more about that soon.

PS -- See David Knoke's SNA Course Syllabus for more well-done materials like the centrality handout I referenced above. David teaches sociology at the University of Minnesota.

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