Entropy of the degree distribution and object-oriented software quality

The entropy of degree distribution has been considered from many authors as a measure of a network's heterogeneity and consequently of the resilience to random failures. In this paper we propose the entropy of degree distribution as a new measure of software quality. We present a study were software systems are considered as complex networks which are characterized by heterogeneous distribution of links. On such complex software networks we computed the entropy of degree distribution. We analyzed various releases of the publically available Eclipse and Net-beans software systems, calculating the entropy of degree distribution for every release analyzed. Our results display a good correlation between the entropy of degree distribution and the number of bugs for Eclipse and Netbeans. Complexity and quality metrics are in general computed on every system module while the entropy is just a scalar number that characterizes a whole system, this result suggests that the entropy of degree distribution could be considered as a global quality metric for large software systems. Our results need however to be confirmed for other large software systems.