Quantifying Technical Debt: A Systematic Mapping Study and a Conceptual Model

To effectively manage Technical Debt (TD), we need reliable means to quantify it. We conducted a Systematic Mapping Study (SMS) where we identified TD quantification approaches that focus on different aspects of TD. Some approaches base the quantification on the identification of smells, some quantify the Return on Investment (ROI) of refactoring, some compare an ideal state with the current state of a software in terms of the software quality, and some compare alternative development paths to reduce TD. It is unclear if these approaches are quantifying the same thing and if they support similar or different decisions regarding TD Management (TDM). This creates the problem of not being able to effectively compare and evaluate approaches. To solve this problem, we developed a novel conceptual model, the Technical Debt Quantification Model (TDQM), that captures the important concepts related to TD quantification and illustrates the relationships between them. TDQM can represent varied TD quantification approaches via a common uniform representation, the TDQM Approach Comparison Matrix, that allows performing useful comparisons and evaluations between approaches. This paper reports on the mapping study, the development of TDQM, and on applying TDQM to compare and evaluate TD quantification approaches.