Abstract
One of the most interesting topics in social network science are social groups, i.e. their extraction, dynamics and evolution. One year ago the method for group evolution discovery (GED) was introduced. The GED method during extraction process takes into account both the group members quality and quantity. The quality is reflected by user importance measure. In this paper the influence of different user importance measures on the results of the GED method is examined and presented. The results indicate that using global measures like social position (page rank) allows to achieve more precise results than using local measures like degree centrality or no measure at all.