An Empirical Study of Social Networks Metrics in Object Oriented Software

We study the application to object-oriented software of new metrics, derived from Social Network Analysis. Social Networks metrics, as for instance the EGO metrics, allow to identify the role of each single node in the information flow through the network, being related to software modules and their dependencies. These metrics are compared with other traditional software metrics, like the Chidamber-Kemerer suite, and software graph metrics. We examine the empirical distributions of all the metrics, bugs included, across the software modules of several releases of two large Java systems, Eclipse and Netbeans. We provide analytical distribution functions suitable for describing and studying the observed distributions. We study also correlations among metrics and bugs. We found that the empirical distributions systematically show fat-tails for all the metrics. Moreover, the various metric distributions look very similar and consistent across all system releases, and are also very similar in both the studied systems. These features appear to be typical properties of these software metrics.