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Critical Path Method (CPM) is a method used to estimate the minimum project duration and determine the amount of scheduling flexibility on the logical network paths within the schedule model.*

  • ES = Earliest Start
  • EF = Earliest Finish
  • LS = Latest Start
  • LF = Latest Finish
  • TF = Total Float = LF – EF
    (amount allowed before affecting end date)
  • FF = Free Float ) = ES2 – EF1
    (amount allowed before affecting subsequent task

* From the Glossary of the Project Management Institute, A Guide to the Project Management Body of Knowledge, (PMBOK® Guide) – Fifth Edition, Project Management Institute, Inc., 20013.

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