Combining Machine Learning and Social Network Analysis to Reveal the Organizational Structures

Formation of a hierarchy within an organization is a natural way of optimizing the duties, responsibilities and flow of information. Only for the smallest organizations the lack of the hierarchy is possible, yet, if they grow, its appearance is inevitable. Most often, its existence results in a different nature of the tasks and duties of its members located at different organizational levels. On the other hand, employees often send dozens of emails each day, and by doing so, and also by being engaged in other activities, they naturally form an informal social network where nodes are individuals and edges are the actions linking them. At first, such a social network may seem distinct from the organizational one. However, the analysis of this network may lead to reproducing the organizational hierarchy of companies. This is due to the fact that that people holding a similar position in the hierarchy can possibly share also a similar way of behaving and communicating attributed to their role. The key concept of this work is to evaluate how well social network measures when combined with other features gained from the feature engineering align with the classification of the members of organizational social network. As a technique for answering the research question, machine learning apparatus was employed. Here, for the classification task, Decision Tree and Random Forest algorithms where used, as well as a simple collective classification algorithm, which is also proposed in this paper. The used approach allowed to compare how traditional methods of machine learning classification, while supported by social network analysis, performed in comparison to a typical graph algorithm.