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Critical path, characteristics and importance

Short answer

The critical path is the longest path from start to end event with zero total float. Its activities have EST=LST and EFT=LFT, its events have zero slack, a delay in any critical activity delays the whole project, and more than one critical path can exist. It gives the minimum completion time and directs management attention and crashing.

Define critical path. Write down its characteristics in the network diagram of project activities and mention its importance.

Definition

The critical path is the longest path (sequence of connected activities) from the start event to the end event of the network. Its length is the project duration, and it is the path with zero total float.

Characteristics

  1. It is the longest path in the network; no other path takes more time.
  2. All activities on it are critical: TF = 0, so EST = LST and EFT = LFT.
  3. Events on it have zero slack: TE = TL.
  4. It runs continuously from the start to the end event.
  5. A network may have more than one critical path.
  6. A delay in any critical activity delays the whole project by the same time.
  7. It can change when activity durations change (a non-critical path may become critical when its float is used).

Importance

  • Gives the minimum project completion time.
  • Shows where management attention and best resources should go.
  • Only critical activities need to be shortened for crashing the project.
  • Float on other activities allows shifting and resource levelling.
  • Base for monitoring, updating and claims for time extension.

✓ Answer checked by Claude Opus 5.5 (high effort)

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