Architecture viewpoints for documenting architectural technical debt

Technical debt (TD) has attracted an increasing interest from researchers and practitioners in the software engineering domain. Currently, most approaches to managing TD focus on dealing with TD at source code level, while few methods deal with TD at architecture level. If architectural technical debt (ATD) is not effectively managed in the architecting process, the knowledge about ATD is not made available to involved stakeholders and the impact of ATD is not considered during architecture decision-making. Thus, the system's maintainability and evolvability can be intentionally or unintentionally compromised. As a result, architectures are costly to maintain and new features are difficult to introduce. To facilitate the management of ATD, it needs to be documented so that it becomes explicit to stakeholders. To this end, we propose a set of architecture viewpoints related to ATD (ATD viewpoints in short). Each viewpoint frames a number of concerns related to ATD. These ATD viewpoints together help to get a comprehensive understanding of ATD in a software system, thereby providing support for architecture decision-making. To evaluate the effectiveness of the ATD viewpoints in documenting ATD, we conducted a case study in a large telecommunications company. The results of this case study show that the documented ATD views can effectively facilitate the documentation of ATD. Specifically, the ATD viewpoints are relatively easy to understand, it takes an acceptable amount of effort to document ATD using the ATD viewpoints; and the documented ATD views are useful for stakeholders to understand the ATD in the software project