Planning schedule contingencies within a project can be used to mitigate some risks in a project. This is especially true in large, complex projects with a lot of unknowns.
The following schedule contingencies could be considered:
- understand the priority of deliverables and requirements and which could be deferred or removed from scope (managing the triple constraints) without impacting project success criteria
- add a block of time (buffer) before the expected completion of a deliverable, milestone, phase, iteration, or increment in the schedule. This distributes the contingency across tasks and the resources responsible for those tasks.
- a project buffer will protect the schedule if critical path tasks are delayed
- feeder buffers protect from delays of non-critical path tasks that feed the critical path
- add contingency to individual task estimates. This is the least recommended alternative because
- Parkinson's law states that people will take as long as you give them. Padding estimates can unnecessarily expand duration
- padded estimates can be difficult to identify
- padded estimates can compromise trust
- extra time for individual tasks does not guarantee success