Impacts of agile requirements documentation debt on software projects: A retrospective study

Documentation debt is a type of technical debt that describes problems in documentation such as missing, inadequate or incomplete artifacts. Unlike traditional methods, agile methodologies usually employ short iterative cycles and rely on tacit knowledge within a team. In particular, Agile Requirements (AR) (e.g., user stories) tend to reduce the focus on requirements specification activities. This scenario contributes to the occurrence of documentation debt. The goal of this paper is to investigate the impact that this type of debt brings to projects developed by using AR. We address this goal by performing a retrospective study in a real software project that used AR in its development. Our analysis was concentrated on data from 132 maintenance and evolution tasks. Of this total, 65 were related to the presence of documentation debt and were performed within a timeframe of 18 months. The findings indicated an extra maintenance effort of about 47% of the total effort estimated for developing the project and an extra cost of about 48% of the initial cost of the development phase.