Quantifying the Analyzability of Software Architectures

The decomposition of a software system into components is a major decision in any software architecture, having a strong influence on many of its quality aspects. A system's analyzability, in particular, is influenced by its decomposition into components. But into how many components should a system be decomposed to achieve optimal analyzability? And how should the elements of the system be distributed over those components? In this paper, we set out to find answers to these questions with the support of a large repository of industrial and open source software systems. Based on our findings, we designed a metric which we call Component Balance. In a case study we show that the metric provides pertinent results in various evaluation scenarios. In addition, we report on an empirical study that demonstrates that the metric is strongly correlated with ratings for analyzability as given by experts.