Fixed Duration is a type of activity where the length of time required to complete the activity remains constant, regardless of the number of people or resources assigned. This means that increasing or decreasing resources does not affect the duration of the task.
Key Aspects of Fixed Duration
- Time Required Is Constant – Task duration is independent of resource allocation.
- More Resources Do Not Reduce Time – Unlike effort-driven tasks, duration remains the same.
- Common in Regulatory & Natural Constraints – Used when external factors dictate the timeline.
- Affects Resource Allocation – Teams may need to plan resource distribution carefully.
Fixed Duration vs. Effort-Driven Work
| Concept | Description | Example |
|---|---|---|
| Fixed Duration | Duration remains the same, even if more people are assigned. | A 24-hour stress test on a server takes the same time, regardless of engineers monitoring it. |
| Effort-Driven Work | Duration changes based on resource allocation. | Writing a 100-page report takes less time if more writers contribute. |
Example Scenarios
Software Development
A security vulnerability scan runs for 48 hours, regardless of how many engineers monitor it.
Construction Project
Concrete curing time is fixed at 7 days, regardless of additional labor availability.
Marketing Campaign
A product launch event lasts 3 days, no matter how many marketers are assigned.
Why Fixed Duration Matters
- Ensures Time-Sensitive Activities Stay on Track – Helps in scheduling regulatory and testing phases.
- Prevents Misallocation of Resources – Avoids unnecessary resource additions where time is non-adjustable.
- Improves Scheduling Accuracy – Helps in planning work that cannot be compressed.
- Supports Risk & Dependency Management – Ensures critical path tasks are well understood.
See also: Effort-Driven Work, Schedule Management, Task Dependencies, Resource Leveling.