Evaluation of simulation-assisted value stream mapping for software product development: Two industrial cases

Context: Value stream mapping (VSM) as a tool for lean development has led to significant improvements in different industries. In a few studies, it has been successfully applied in a software engineering context. However, some shortcomings have been observed in particular failing to capture the dynamic nature of the software process to evaluate improvements i.e. such improvements and target values are based on idealistic situations.Objective: To overcome the shortcomings of VSM by combining it with software process simulation modeling, and to provide reflections on the process of conducting VSM with simulation.Method: Using case study research, VSM was used for two products at Ericsson AB, Sweden. Ten workshops were conducted in this regard. Simulation in this study was used as a tool to support discussions instead of as a prediction tool. The results have been evaluated from the perspective of the participating practitioners, an external observer, and reflections of the researchers conducting the simulation that was elicited by the external observer.Results: Significant constraints hindering the product development from reaching the stated improvement goals for shorter lead time were identified. The use of simulation was particularly helpful in having more insightful discussions and to challenge assumptions about the likely impact of improvements. However, simulation results alone were found insufficient to emphasize the importance of reducing waiting times and variations in the process.Conclusion: The framework to assist VSM with simulation presented in this study was successfully applied in two cases. The involvement of various stakeholders, consensus building steps, emphasis on flow (through waiting time and variance analysis) and the use of simulation proposed in the framework led to realistic improvements with a high likelihood of implementation.