Critical Path Method
Person Unit
: Determines the time taken by one person to complete a task
Units of Effort
- Person Days
- Person Months
- Person Weeks
Minimum Duration of a Project
- The minimum possible duration at the end of the structure
- i.e.
e: 27
- i.e.
Critical Task / Path
- A project has at-least one critical path.
- It may have more than one critical path.
- The pre-req of a critical task is also a critical task
- We start mapping out the critical path from the trail
(end)of the diagram.
Insight
Tasks that cannot be delayed without affecting the project finish date are the critical tasks.
Important
By definition, if a task has two pre-required tasks, then the one with the max time is the critical task
Non-Critical Tasks
- We can afford some delays in these.
Paths
| Path Sorted in descending order w.r.t | Duration |
|---|---|
| S → RE → A&D(B) → I(A) → T → F | 27 |
| S → RE → A&D(B) → I(B) → T → F | 25 |
| S → RE → A&D(A) → I(A) → T → F | 24 |
| S → RE → A&D(C) → I(B) → T → F | 20 |
Bold one is the critical path
Lags
- We determine the lag using these paths to get the optimal path.
- Sort out the paths according to duration in descending order .
- Compare every new path with the critical path (take the difference).
- For new nodes in the compared path, put the difference as lag time.
- Starting from top to bottom in the sorted list.
Link