Lesson 2 of 4
What a Task represents
A Task is a rounded rectangle. It represents a single, atomic unit of work performed by a person, team, or system. 'Atomic' means it does not need to be broken down further at this level of the diagram — the step is simple enough to be understood as one action.
One task per actor per action
If two different people need to do something, that is two tasks. If one person does the same action twice in different contexts, consider whether they are truly the same step or two distinct tasks in different parts of the flow.
Example: 'Review Invoice' is one task assigned to a Finance Clerk. 'Approve Invoice' is a separate task assigned to the Finance Manager. Even though they are sequential steps in the same approval flow, they are performed by different people — separate tasks in separate lanes.
Task markers (advanced mode)
| Marker | Task type | When to use |
|---|---|---|
| Person icon | User Task | A human performs this task manually |
| Gear icon | Service Task | A system performs this automatically with no human intervention |
| Envelope icon | Send Task | The process sends a message as the task itself |
| Envelope with arrow | Receive Task | The process waits to receive a message as the task itself |
| Loop arrows | Looping Task | The task repeats until a condition is met |
| None (no marker) | Abstract Task | Default — type unspecified; appropriate for descriptive BPMN |
For BA/PM diagrams
You do not need task markers in descriptive BPMN. Abstract Tasks (no marker) are sufficient for business-level process documentation and are cleaner to read. Add markers only when you need to distinguish manual from automated steps.
Task vs. Sub-process: when to escalate
Use a Task when the work is a single step that does not need to be broken down at this level. Use a Sub-process (a task shape with a `+` sign in the bottom centre) when the step contains multiple internal steps that matter to the audience — and those steps would clutter the main diagram.
Example: In a high-level invoice approval diagram, 'Handle Invoice Discrepancy' is shown as a Task. If you need to detail what that involves — contact supplier, log discrepancy, chase response, re-review — you expand it into a Sub-process with its own diagram.
Common mistake
Using a Task to represent a decision. 'Check if approved' is not a task — it is a Gateway. A Task is always work performed by someone. A Gateway is always a routing decision. Blurring this distinction produces diagrams where it is unclear whether a shape represents doing something or deciding something.
✓ When to use
- Every discrete, atomic unit of work performed by a defined actor
- Sub-process when a task contains 3 or more internal steps the audience needs to see
- Add task markers when you need to distinguish automated from manual work
✗ When not to use
- ✕Don't use a Task to represent a decision — use an Exclusive Gateway
- ✕Don't bundle multiple actions into one Task to simplify — split them if they belong to different actors
- ✕Don't add task markers in descriptive BPMN unless it adds meaningful information