Unity criteria for Business Process Modelling

Software engineering has a recurrent problem in relation to business process modelling (BPM): there is no agreement with regards to business process modularity. We claim that this results from a lack of theoretical underpinnings on the matter. This paper goes deeply into this issue by unfolding the notion of modularity: modularisation has an engineering intention that depends on the field where it is applied, and it relies on information hiding and encapsulation mechanisms. Unity criteria provide guidance for encapsulation. An important contribution of the paper is to provide unity criteria for BPM. These criteria are mainly underpinned by systemic principles and communication theory. The resulting unity criteria allow to clearly differentiate between problem space and solution space in BPM. The argumentations are illustrated with explanatory examples and figures. Also, a historical review of unity criteria in software engineering and requirements engineering is offered.