An empirical investigation of the impact of architectural smells on software maintainability

In recent years, interest in the potential influence of architectural smells on software maintainability has grown. Yet, empirical evidence directly linking maintainability quality attributes — such as modularity and testability — with architectural smells is scarce. This study analyzes seven architectural smells across 378 versions of eight open-source projects. We developed a tool to gather data on architectural smells, associated projects, and package-level quality attributes. The empirical findings reinforce that certain architectural smells indeed correlate with specific quality attributes - a notion previously backed merely by argument. Most architectural smells negatively correlated with project-level testability but not project-level modularity. While there is not a consistent negative correlation with testability at the package level, many smells display a pronounced negative association with the maintainability quality attributes. • The size of projects has a significant impact on both modularity and testability. • Architectural smells show a negative relationship with testability. • Addressing Dense Structure smell can improve modularity and testability. • Addressing God Component smell can improve modularity and testability. • Addressing Scattered Functionality smell can improve modularity and testability.