The Risk of Generating Technical Debt Interest: A Case Study

Technical Debt (TD) interest refers to the extra maintenance costs incurred by the very existence of TD items in a system. The generation of TD interest can make or break a system: too little interest and the effect of TD is negligible; too much interest and the system becomes unsustainable. In this paper, we consider the generation of interest as a risk and present a metric to quantify this risk. Subsequently, we validate this metric in two ways. First, we explore whether the metric can be effectively used to prioritize TD remediation. Second, we investigate if adding new code reduces the risk of interest generation. The results of the study suggest that: (a) the proposed risk management metric is capable of efficiently prioritizing TD items; and (b) that the new code that is introduced in the system is usually less risky for producing interest, compared to legacy code.