The Relation Between Documentation and Internal Quality of Software

Abstract

Regardless of the software development process used, there are many factors that take place during such process. Those factors may affect positively or negative the internal quality of the resulting software product. In the context of open source software, the success of a project depends on having a community in which people can contribute to expand and improve the project. How modular and easy-to-modify a system is, is one of many factors that developers take into consideration before contributing to a project. Therefore, creators of open source projects need to ensure that their system has certain level of internal quality and modularity in order to make it easier for contributors around the world to modify and extends the system. Therefore, understanding the factors that affect the quality of software product is the first step towards developing software of higher internal quality. This study investigates the effect that factors such as documentation quality, size of a system, and documentation size have on a specific internal quality metric: Coupling Between Objects or CBO. Open Source Software projects were selected for this study. Their internal quality over time was studied as well as the quality and content of their documentation. Finally, a Spearman’s correlation analysis revealed the correlation between documentation quality, size of a system, and documentation size with the metric CBO. Our results suggest a strong positive correlation between the CBO metric and factors such as lines of code, number of modules, and documentation size. Such results indicate that as the size of the system increases (size expressed as lines of code or number of modules), the CBO of the system increases as well. The same is true for amount of documentation files. As it increases, so does the CBO of the system. This study further explains such results and discusses the possible causes of the correlations.