Measuring and Visualizing Code Stability -- A Case Study at Three Companies

Monitoring performance of software development organizations can be achieved from a number of perspectives - e.g. using such tools as Balanced Scorecards or corporate dashboards. In this paper we present results from a study on using code stability indicators as a tool for product stability and organizational performance, conducted at three different software development companies - Ericsson AB, Saab AB Electronic Defense Systems (Saab) and Volvo Group Trucks Technology (Volvo Group). The results show that visualizing the source code changes using heat maps and linking these visualizations to defect inflow profiles provide indicators of how stable the product under development is and whether quality assurance efforts should be directed to specific parts of the product. Observing the indicator and making decisions based on its visualization leads to shorter feedback loops between development and test, thus resulting in lower development costs, shorter lead time and increased quality. The industrial case study in the paper shows that the indicator and its visualization can show whether the modifications of software products are focused on parts of the code base or are spread widely throughout the product.