A process hierarchy diagram (or functional decomposition diagram) provides a graphical view of the functions of a system and helps you decompose them into a tree of sub-processes.
-
Define all the processes performed in the scope of a business function
-
Focus on process recognition and enumeration - only process names are defined at this step
-
Decompose already identified processes into sub-processes until an appropriate atomic level is reached. The top level in the hierarchy might represent your organization, with the first level of decomposition representing departments, the second level department projects, and the third level activities required to advance these projects, etc.
Note: If you are working with the Data Flow Diagram process language, you can analyze each process at the first level of your hierarchy in its own context diagram to show the primary relationships between the organization and the external entities with which it deals (see Data Flow Diagram (DFD)). -
Reorganize sub-processes, if necessary, by changing their parent
-
Display in a single view the whole hierarchy of an already described process or of any decomposed sub-process
In the following example, the root process, Marketing, is decomposed into three sub-processes, Paper Advertising, Email Campaign, and Corporate Web Site. The latter is in turn decomposed into two sub-processes, and so on:
Expand the hierarchy to display further children below decomposed processes by clicking the + sign on the base of the process, or hide children by clicking on the - sign on the base of their parent. Alternatively, right-click a process and select Expand to show one level of children, Expand All to show all levels, or Collapse to hide all children.
Each of these processes can be analyzed in its own business process diagram (see Business Process Diagrams).