WBS, EPS & Types
Project Task Types: Fixed Units, Fixed Duration, Fixed Work
Fixed Units, Fixed Duration, Fixed Work + MSPDI integers
Formula (Microsoft): Work = Duration × Units.
Fixing one value tells Project not to change it when the other two change.
| Task type | If you revise units | If you revise duration | If you revise work |
|---|---|---|---|
| Fixed Units (default) | Duration recalculated | Work recalculated | Duration recalculated |
| Fixed Work | Duration recalculated | Units recalculated | Duration recalculated |
| Fixed Duration | Work recalculated | Work recalculated | Units recalculated |
- Fixed Units: people (units) stay put. Default. File > Options > Schedule sets the default for new tasks.
- Fixed Work: work stays put. Always effort-driven; you cannot turn effort-driven off.
- Fixed Duration: duration stays put (meetings, curing time).
MSPDI integers
Microsoft Learn, Task Type element:
| Value | Meaning |
|---|---|
| 0 | Fixed units |
| 1 | Fixed duration |
| 2 | Fixed work |
Interaction with effort-driven
Effort-driven is a separate yes/no except on Fixed Work (always on). See effort-driven.md. Adding a resource to a Fixed Units + effort-driven task shortens duration; adding a resource to a Fixed Duration + effort-driven task reduces work per resource.
P6 duration_type is a different enum (Fixed Units, Fixed Duration & Units, Fixed Units/Time, etc.). Do not assume the integers match. Mapping is conversion work, not identity.