Chapter 6 Centrality and Centralization

In Week 5, we explored a range of network-level measures, including size, density, diameter, average path length, centralization, reciprocity, transitivity, clustering coefficient, and so on. There are other interesting measures not covered by the textbook but worth your attention:10

  • Cohesion: The degree to which actors are connected directly to each other by cohesive bonds.
  • Structural cohesion: The minimum number of members who, if removed from a group, would disconnect the group.

You have done a phenomenonal job digging into different concepts and measures and sharing your findings back to the group via annotations. A shout-out to HopeinJ for asking an important question:

@bech0079, I don’t quite understand the difference btw the network.density between the network.density and edge.density, both gives the ratio between extant edges/potential edges.https://www.rdocumentation.org/packages/network/versions/1.13.0/topics/network.density Do you have any idea on that?

I want to take this opportunity to mention that there is a “universe” of R packages, the dependencies among which can be visualized as a giant graph (see this page). Among these packages, there are many packages developed for SNA. The network package mentioned by HopeinJ is another R package that can be used for SNA. In igraph, please use [edge_density](https://www.rdocumentation.org/packages/igraph/versions/1.2.4/topics/edge_density) to compute network density.

Please make sure to check our Hypothes.is annotations to learn about contributions from other colleagues. If there are burning questions, please continue the discussion on Slack.

This week, we will:

  • Engage with node-level measures in social networks
  • Understand how network-level and node-level measures are connected
  • Learn to calculate node-level measures using SNA applications

  1. Note that the description of models introduced here may not fit the philosophical worldview you feel comfortable with or subscribe to. Refer back to Section @ref{threelevels} for an earlier discussion we had about aligning methodology and philosophical viewpoints.