Do software categories impact coupling metrics?

Software metrics is a valuable mechanism to assess the quality of software systems. Metrics can help the automated analysis of the growing data available in software repositories. Coupling metrics is a kind of software metrics that have been extensively used since the seventies to evaluate several software properties related to maintenance, evolution and reuse tasks. For example, several works have shown that we can use coupling metrics to assess the reusability of software artifacts available in repositories. However, thresholds for software metrics to indicate adequate coupling levels are still a matter of discussion. In this paper, we investigate the impact of software categories on the coupling level of software systems. We have found that different categories may have different levels of coupling, suggesting that we need special attention when comparing software systems in different categories and when using predefined thresholds already available in the literature.