PERT and CPM are complementary tools, because "CPM employs one time estimate and one cost estimate for each activity; PERT may utilize three time estimates (optimistic, expected, and pessimistic) and no costs for each activity.
PERT和關鍵路徑法（CPM）是互補的工具，因為“CPM採用了對每一個任務活動，只做一次的估計和成本估算；PERT則可能會利用三個時間點來估計（樂觀，預期和悲觀），並且每個活動都沒有成本估計。