Part 87: Critical Path Method

//Part 87: Critical Path Method
Part 87: Critical Path Method2022-08-21T03:58:05+00:00

Part 87: Critical Path Method
(Project Schedule Management: Develop Schedule)
(Project Schedule Management: Control Schedule)

  • Critical Path Method is used to estimate minimum project duration
  • We can determine amount of scheduling flexibility on the logical network paths within the schedule
  • We take the Schedule Network and figure out what the longest path is
    • This is the shortest amount of time that the project can be completed in
    • It is called the Critical Path
  • Our process calculates Early Start, Late Start, Early Finish, and Late Finish dates for each activity, without considering resource limitations
    • Early Start = Earliest time an activity can start
    • Early Finish = Earliest time an activity can finish
    • Late Start = Latest time an activity can start
    • Late Finish = Latest time an activity can finish
  • If we’re able to delay an activity from its early start date and not affect the project’s finish date or a schedule constraint, then we have a “float”, known as a Positive Float
  • On a project, we can have a Negative Float when the amount of time allocated to the project is less than the amount of time required to complete it
  • There can be multiple pathways throughout the project
    • We can measure the float in each pathway
    • On the Critical Pathway, we should have zero float because this is the shortest possible duration of the project.  Any increase in the Critical Pathway will delay the conclusion of the project.
    • We can have several “near-critical” paths
  • If we have a problem
    • We can adjust the activity durations (by adding more resources or reducing scope)
    • We can adjust logical relationships (if they are discretionary)
    • We can adjust leads and lags
  • For example, we have two pathways in the diagram below
    • Pathway A – B – D
      • This is not a critical path
      • Activity B can be completed in 9 days
      • We can start activity B on any day between day 15 and day 20, without delaying the rest of the project (activity C won’t start until day 21)
      • Therefore, we can delay activity B by up to 5 days, and we have a total float of 5 days
    • Pathway A – C – D
      • This is the critical path because there is no Float
      • Activity A will take us 6 days to complete
      • Activity C will take us 14 days to complete
      • Activity D will take us 20 days to complete
      • The total project time is 40 days
      • If we delay