The influence of using collapsed sub-processes and groups on the understandability of business process models

Many factors influence the creation of understandable business process models for an appropriate audience. Understandability of process models becomes more critical as the size and complexity of the models increase. Using vertical modularization to decompose such models hierarchically into modules is considered to improve the understandability of these models. To investigate this assumption, two experiments were conducted. The experiments involved 2 large-scale real-life business process models that were modeled using BPMN v2.0 (Business Process Model and Notation) in the form of collaboration diagrams. Each process was modeled in 3 modularity forms: fully-flattened, flattened where activities are clustered using BPMN groups, and modularized using separately viewed BPMN sub-processes. The objective was to investigate if and how different forms of modularity representation (used for vertical modularization) in BPMN collaboration diagrams influence the understandability of process models. In addition to the forms of modularity representation, the presentation medium (paper vs. computer) and model reader’s level of business process modeling competency were also investigated as factors that potentially influence model comprehension. 60 business practitioners from a large organization and 140 graduate students participated in our experiments. The results indicate that, when these three modularity representations are considered, it is best to present the model in a ‘flattened’ form (with or without the use of groups) in the ‘paper’ format in order to optimally understand a BPMN model. The results also signify model reader’s business process modeling competency as an important factor of process model comprehension.