Critical path can be used by the Project Manager to focus on which project activities can NOT slip or the project will slip and use to calculate Float focus on which project activities can not slip or the project will slip and also but it does NOT help, if the schedule is delayed focus on which project activities can slip or the project will slip and use to calculate Float focus on which project activities can not slip and work with team members to prevents slip. AND, if the schedule is delayed, the project will slip so critical path can be used to rerrange the schedule to "buy back" time if possible