Expressiveness and Understandability Considerations of Hierarchy in Declarative Business Process Models

Hierarchy has widely been recognized as a viable approach to deal with the complexity of conceptual models. For instance, in declarative business process models, hierarchy is realized by sub-processes. While technical implementations of declarative sub-processes exist, their application, semantics, and the resulting impact on understandability are less understood yet—this research gap is addressed in this work.

In particular, we discuss the semantics and the application of hierarchy and show how sub-processes enhance the expressiveness of declarative modeling languages. Then, we turn to the impact on the understandability of hierarchy on a declarative process model. To systematically assess this impact, we present a cognitive-psychology based framework that allows to assess the possible impact of hierarchy on the understandability of the process model.