- displays the critical path: activities that must be done end to end
- reveals flexibility: places we can optimize resources to increase delivery
this visual representation of all the activities that must be done in a particular order is invaluable to understand a project
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Critical Path method
this method is used to map the shortest path possible to project completion, it also reveals the tasks that if delayed will ultimately delay the project delivery. The critical path is the longest path from project start to finish whereas the non-critical paths can be adjusted in duration within reason and not affect the project delivery date.
With the network diagram complete and our critical path identified we can look at our alternative paths and identify their slack or float value, that is the amount of time from the earliest start date for each activity that can be deferred or extended without pushing the projects delivery date.
To Identify our critical path
Forward pass analysis
is the process of moving through each path identifying the earliest start and end date for each activity.
- Earliest start date (ES) is the earliest date that an activity can begin with respect to it's predecessor relationships
- Earliest finish date (EF) is the earliest date that an activity can finish, (ES + duration)
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float: is between paths is the difference between the duration of the critical path and all alternative paths, each alternative path has it's own float value, that value is how many days that path can be delayed without delaying the project
Backward pass analysis
The backward pass analysis is the process of moving from the end of our project back to the beginning to determine the latest start date and the latest finish date for each activity
- Latest start date (LS) is the latest date an activity can start without delaying the project delivery. (LF - Duration)
- Latest finish date (LF) is the latest date that an activity can finish without delaying the project delivery.
Activities who's ES & EF values are the same as their LS & LF values are on the critical path.
the difference between an activities LS and ES is the float
