A BPMN “Activity” is a step in a process, where somebody or something does something.
The rounded box is a BPMN activity. An activity may be at the lowest level of modelling, in which case it may be termed a task. When it has sub-structure, it is usually termed a process, though activity & process (and task) are more commonly used interchangeably.
Where the activity has sub-structure, the plus sign denotes that.
BPMN doesn’t mandate a numbering scheme, so if we want to employ one, it’s going to be a local standard. Numbering is a good idea, since the common process names will occur all over the place e.g. ‘Check Application’ or ‘Verify payment’.
You may be used to naming the links between activities. This isn’t allowed in BPMN, because such annotations may hide decisions that we need to make explicit.
The naming of processes, like cats, is a serious business. Pick a bad name, and the analysis will get confusing. Sticking to the Verb+noun formula rarely causes problems.
Calling a process ‘Have shower’ is OK. Calling it just ‘shower’ is less clear: is this a thing (BPMN Artefact) or an exhortation?
Getting clever with Activities
Our Core set of activities has just three types:
• Abstract ones, which just means we haven’t given them one of the other types. If in any doubt at all, use this
• Manual ones – where people are doing things
• Service ones – where some system somewhere is doing something, without a person being involved
There are others, but they are not in our core set.