Technical debt interest assessment: From issues to project

The interest of Technical Debt (TD) is difcult to calculate, especially on a project level. Current approaches are based on fne-grain issue assessment, but there is no evidence about how TD is assessed on a project level. A few tools use an aggregation function that sum the TD issues on a project level. We conducted a multiple case-study on four diferent projects. We asked the project teams to assess the TD both on an issue level and on a project level. We also asked the product manager and a senior developer to assess the TD on a project level. We found that the function mapping the interest of TD to a project overall is not the sum of issue-level TD. We report the quantitative results of the performed experiment and we also developed a qualitative explanation of the results based on interviews with the development team. This paper represents a frst step towards assessing the interest of TD at a project level