Are Relevant the Code Smells on Maintainability Effort? A Laboratory Experiment

In Software Engineering, maintainability is considered a non-functional feature that gives the software the ability to be modified effectively and efficiently. In the late 1990s, code smells emerged as a way to approach potential failures. Although the link between code smells and effort has been studied, there are few quantitative studies trying to demonstrate the relationship between code smells and effort of maintenance. In this paper an experiment is used to analyze whether there are any differences in effort when performing perfective maintenance with and without a code smell. However, no significant differences were found between the control group and the experimental group, indicating that elimination of code smells would not substantially impact effort. The result is relevant because refactoring efforts appear not having a significative effect on maintainability. Finally, the presence of a threshold of code smells concentration would make it possible to determine when refactoring would become a viable activity.