To Be or Not to Be Central: On the Stability of Network Centrality Measures in Shakespeare's "Hamlet"

Centrality measures derived from character networks can be used to detect the main characters in a play. For example, previous research has shown that characters with high network centrality typically perform the majority of speech acts and appear in most of the scenes. However, one can extract character networks from plays in various ways. Close reading may omit minor characters like attendants or servants, while distant reading (e.g., parsing an XML file) may include aggregate characters like "All", "Both Lords", or similar. Furthermore, the networks may display either implicit or explicit connections, depending on whether we connect characters because they appear in the same scene or because they are directly addressing each other, respectively. Thus, as adding more characters or connections to the network affects centralities and other network measures, the interpretation of both qualitative and quantitative aspects of character networks depends on the extraction method. In this work we are concerned with the specific question whether details of the textual source and the extraction method, such as adding minor or aggregate characters, make main characters less "central". Answering this question will allow us to better assess the validity of automated literary network analysis.