Multilayer Network Model for Analysis and Management of Change Propagation

A pervasive problem for engineering change management is the phenomenon of change propagation by which a change to one part or element of a design requires additional changes throughout the product. This paper introduces a multilayer network model integrating three coupled layers, or domains, of product development that contribute to change propagation: namely, the product layer, change layer, and social layer. A baseline repository of tools and metrics is developed for the analysis and management of change propagation using the model. The repository includes a few novel tools and metrics, most notably the Engineer Change Propagation Index (Engineer-CPI) and Propagation Directness (PD), as well as others already existing in the literature. As such, the multilayer network model unifies previous research on change propagation in a comprehensive paradigm. A case study of a large technical program, which managed over 41,000 change requests in eight years, is employed to demonstrate the model’s practical utility. Most significantly, the case study explores the program’s social layer and discovers a correspondence between the propagation effects of an engineer’s work and factors such as his/her organizational role and the context of his/her assignments. The study also reveals that parent-child propagation often spanned two or more product interfaces, thus confirming the counterintuitive possibility of indirect propagation between nonadjacent product components or subsystems. Finally, the study finds that most changes did not lead to any propagation. Propagation that did occur always stopped after five, and rarely more than four, generations of descendants.