Network analysis technique used in complex project plans with a large number of activities. CPM diagrams (1) all activities, (2) time required for their completion, (3) and how each activity is related to the previous and next activity. A sequence of activities is called a 'path,' and the longest-path in the diagram is the critical path. It is 'critical' because all activities on it must be completed in the designated time, otherwise the whole project will be delayed. Also called critical path analysis or critical path methodology.