Making Technical Debt Visible Using Hybrid Sankey Diagrams: An Industrial Case Study

Abstract

Context: Technical debt (TD) is a challenge for companies who develop software on which their critical operations depend. To properly manage TD, it is necessary to make it visible to the different stakeholders involved to support informed decisions. Objective: To validate a TD visualization approach based on hybrid Sankey diagrams that makes the TD visible by showing (a) technical and business aspects, and (b) the flow of value and TD impacts. This approach regards visualizations as boundary objects. Method: We performed a multi-case study in a large multi-industry state-owned company. The objective was to validate the effectiveness of such visualizations and to explore their possible uses in TD management. We first used a retrospective case study on a TD decision-making scenario and, later, visualization usage scenarios using focus groups to evaluate its usefulness. Results: The results suggest that the proposed approach: (a) provides a structured process for systematic TD visualization to help the decision-making process; (b) enables the communication at knowledge boundaries between stakeholders to make informed decisions; (c) uses flow representations that are important for assessing the impact in multiple functional areas; and (d) enables documentation and reuse. Conclusion: The study results suggest that TD decision-making events can benefit from using our TD visualizations based on hybrid Sankey diagrams as boundary objects to portray the impact of TD in business, services, and technical aspects.