# On the Relationship between Self-Admitted Technical Debt Removals and Technical Debt Measures
## 1 Introduction  
During the evolution of a software system, several problems can occur leading to the decreasing of the quality measures and introducing technical debt. Some of these approaches are more subjective, while some others are more objective and based on the development assertions. In the literature, there are some approaches based on the assessment of metrics to identify problems concerned with well-known principles of object-oriented design [1; 2]. While other studies focused on the architectural-level proposed approach for the identification of technical debt at that level.  
In [3], the metrics on a package are used for the identification of architectural technical debt, while in other studies, the comments extracted from the code were used [4; 5]. In [6], the authors analyzed the structure of code with the aim of visualizing the technical debt at the architectural level. Differently from these studies in [7], the authors used a scenario of changes to identify technical debt.  
Self-admitted technical debt (SATD) refers to the admission of technical debt by developers through the use of comments or references in commit messages. In the literature, several studies have deepened the SATD, evaluating it from different perspectives, such as its diffusion, the consequences that derive from it on the quality of the software, and the consequent removal.  
In this document, we examine the removal of SATD to understand if it affects objective measures of technical debt values. In particular, the goal is to verify whether the value of the technical debt for a given file is reduced in the comments in which the developers report their removal.  
Therefore, the trends of the technical debt values are evaluated in open source software projects. In particular, the study aims to investigate the differences between the value of the technical debtobtained through an objective measure, namely measured with the SonarQube platform, and the self-admitted technical debt reported by the developers and collected in a dataset [8].  
This dataset labels four different types of change that can be used to remove the technical debt in the source code: class removal, method removal, modified method, and unchanged method.  
To perform a deeper investigation on what happens when SATD removals occur, a further analysis has been performed to assess the correlation between the variations of the technical debt and the values of the object-oriented metrics, including Chidamber and Kemerer metrics [9]. The analysis aims to verify if it is possible to observe a consistency change between the results obtained for the technical debt measure changes and the changes in the object-oriented metrics mentioned above.  
Section 3 contains the research questions that have been studied. The results obtained show that in the classes in which the removals of SATD were recorded, the value of the technical debt decreases considerably, until it disappears. Moreover, the values of Object-Oriented (OO) quality metrics, including Chidamber & Kemerer metrics, improve their values by a low percentage with respect to the SATD removals considered. These findings can be used for a better understanding of the numerous approaches used for the identification and measurement of technical debt in the software system.  
The rest of the paper is structured as follows: Section 2 describes primarily related works, Section 3 defines the design of the study, the obtained results are reported in Section 4, while conclusions and future work are outlined in the last section.