Quantifying TD Interest: Are we Getting Closer, or Not Even That?

Despite the attention that Technical Debt has attracted over the last years, the quantification of TD Interest still remains rather vague (and abstract). TD Interest quantification is hindered by various factors that introduce a lot of uncertainty, such as: identifying the parts of the system that will be maintained, quantifying the load of maintenance, as well as the size of the maintenance penalty, due to the existence of TD. In this study, we aim to shed light on the current approaches for quantifying TD Interest by exploring existing literature within the TD and Maintenance communities. To achieve this goal, we performed a systematic mapping study on Scopus and explored: (a) the existing approaches for quantifying TD Interest; (b) the existing approaches for estimating Maintenance Cost; and (c) the factors that must be taken into account for their quantification. The broad search process has returned more than 1,000 articles, out of which only 25 provide well-defined mathematical formulas/ equations for the quantification of TD Interest or Maintenance Cost (only 6 of them are explicitly for TD Interest). The results suggest that despite their similarities, the quantification of TD Interest presents additional challenges compared to Maintenance Cost Estimation, constituting (at least for the time being) the accurate quantification of TD Interest an open and distant to solve research problem. Regarding the factors that need to be considered for such an endeavor, based on the literature: size, complexity, and business parameters are those that are more actively associated to TD Interest quantification.