Tuesday, November 12, 2013

Network Analysis of Facebook Groups

A very interesting concept which I learnt in the Business Intelligence class was about Network Analysis. The various insights regarding their applications and metrics were extremely interesting. As a part of our curriculum we were required to use a very user-friendly network analysis tool called Gephi. This tool takes the input in the form of a .gdf file and creates a network consisting of nodes and edges. Various measures can be calculated and the network can be visually analyzed. For my homework, I performed the analysis for un-directed and un-weighted network. To gain more insights into the tool and understand the metrics better, I wanted to perform analysis on a directed weighted network. This blog post describes various interesting insights I observed after performing the analysis.

For my analysis, I picked the Eller MIS at the University of Arizona group as it is common to most of us. I extracted the Eller MIS facebook group data using netviz and imported it in gephi. After importing the data, defining the properties and using YifanHu's Multilevel algorithm the below visualization was obtained

where the green color nodes are the users, the red nodes are posts being posted by the group and the blue color nodes are posts being by users of the group.

When we analyze the portion of the network, we can clearly see that the center node has many users posting the relevant post. On a closer examination, we can see that the the node represents the post regarding the US News ranking of the MIS department. This is the most prominent node which has a high in-degree.

Another interesting fact which we can observe it that one user has posted a particular post multiple times (Has a high weight on the edge). On closer examination of the node, it is found that the particular post was regarding the tuition fee of Eller. This shows that this particular user is interested in knowing the exact tuition fee. Another post which is posted more often by a single user is regarding the issues during accessing a particular page of the Eller website. From this we can say that the users use this group as a forum to discuss various questions.
On running the various metrics, the below values were obtained:

We can see that the density of the graph is very less. This clearly indicates that the people in this group are not closely connected to one another. The modularity is high which shows that even if it is not densely populated the individual modules are densely connected. Another interesting fact is the network diameter is just 1. This shows that the network is not very spread out and most users can reach other users with one hop. This is because the group is a small group and the metrics also prove it. This graph also has 158 strongly connected components which indicates that there are a lot of direct routes between two nodes in this network.

From the above analysis, it can be concluded that the Eller MIS group in Facebook has sparsely populated network with the main emphasis being on posts related to the program and also the it serves as a forum to discuss concerns and queries. 

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