EPC vs. UML Activity Diagram - Two Experiments Examining their Usefulness for Requirements Engineering

Business process modeling notations are used in requirements engineering to specify business processes that should be supported by the system under development. Comparisons of business process modeling notations with regard to their concepts do exist, but to our knowledge, little evaluation has taken place regarding their effectiveness and efficiency for typical requirements engineering tasks. Therefore, we set up experiments examining UML activity diagrams (ACTs) and event-driven process chains (EPCs) both from a requirements engineer's perspective with a focus on model creation and from a customer's or end user's perspective with a focus on model understandability. The experiments were conducted as a blocked subject-object study, where the participants had to solve several characteristic tasks. The results were then analyzed by means of statistical analysis methods. In the case of the requirements engineer, we were able to show that ACTs perform better than EPCs. In the case of the customer or end user, we cannot make a clear statement.