BPMN21 — Task Description -- Internal Conflict

Sect 10.3.3 states, "A Task is used when the work in the Process cannot be broken down to a finer level of detail."

However, the task definition in the glossary states, "A Task is used when the work in the Process is not broken down to a finer level of Process Model detail."

The phrase, "cannot be broken down" is much different than the phrase, " is not broken down". The latter suggests that an activity could be broken down further, but was not.

The glossary definition is correct since a task can often be broken down into tiny actions (e.g., Click the left mouse button), but a person modeling the process may choose not to model to that low a level. Thus, a task is the lowest level shown on a diagram, but may not necessarily be the lowest possible level.

Recommend that the sentence in Sect 10.3.3 be changed to be consistent with the one in the glossary. As an option, you also may wish to make that statement, "Any conflicts between the glossary and other parts of the specification, the glossary takes precedence."