Graph-based ranking algorithms for e-mail expertise analysis

In this paper we study graph--based ranking measures for the purpose of using them to rank email correspondents according to their degree of expertise on subjects of interest. While this complete expertise analysis consists of several steps, in this paper we focus on the analysis of digraphs whose nodes correspond to correspondents (people), whose edges correspond to the existence of email correspondence between the people corresponding to the nodes they connect and whose edge directions point from the member of the pair whose relative expertise has been estimated to be higher. We perform our analysis on both synthetic and real data and we introduce a new error measure for comparing ranked lists.