Collaboration analysis in recommender systems using social networks

Many researchers have focused their efforts on developing collaborative recommender systems. It has been proved that the use of collaboration in such systems improves performance, but what is not known is how this collaboration is done and what is more important, how it has to be done in order to optimise the information exchange. The collaborative relationships in recommender systems can be represented as a social network. In this paper we propose several measures to analyse collaboration based on social network analysis. Once these measures are explained, we use them to evaluate a concrete example of collaboration in a real recommender system.