In the first two installments of this series, we saw why BPMN is important to the Business Process Expert and got an overview of the notation. In this part, we’ll look beyond the spec to suggest some best practices for making your BPMN models most effective.
The art of effective process modeling depends on what you are trying to do. Unlike traditional notations, which presuppose a particular methodology, BPMN is methodologyneutral, and can be used for multiple purposes. The first, which I call Level 1, is simply qualitative description, a diagram of the as-is (or proposed to-be) business process that stakeholders can gather around, discuss, and improve. Level 1 models may ignore exceptions and show only the “happy path,” and may not include every step, just those significant for discussion and qualitative analysis.
The second, which I call Level 2, describes all the activities and flows in the process, including exceptions, and pays particular attention to their sequential and concurrent relationships. The goal of Level 2 modeling is a complete business-intelligible description of the process sufficient for quantitative analysis. Level 2 models contain all the detail required for accurate simulation, but are not by themselves executable. Level 2 modeling is still a business – or BPX – function. It does not require technical knowledge of the implementation of each activity, essentially just the activity’s name, performer, and possible exceptions. The rules embodied in the BPMN spec mostly apply to modeling at Level 2.
Level 3 modeling refers to using BPMN in executable process design, typically in a BPM Suite. It is similar to Level 2 modeling, but most tools that leverage BPMN as part of their executable design environment diverge here and there from the spec, since not everything that can be drawn in BPMN may be executable on the BPMS’s process engine, and even when the engine can implement the BPMN semantics, the executable design may not describe it in accordance with BPMN. Thus BPMN at Level 3 is, today at least, vendorspecific in its details.
So in this article, when I talk about the art of effective process modeling, I really mean at Level 2.
Author: Bruce Silver