Schedule & Critical Path: What Governs Your Project Duration?
Compress the critical path, not the rest.
- Node — An activity
- Arrow — A dependency or sequence
- Critical path — The longest path, highlighted in color
Activities are arranged in a network diagram by their dependencies. The critical path is the longest chain of linked activities and it determines the project shortest possible duration; its activities have no float, so any delay on them delays the whole project. To shorten duration when needed: crashing by adding resources to critical activities, or fast-tracking by running activities in parallel; both raise cost or risk. To balance resource loading: resource leveling which may extend duration, or resource smoothing within available float.
Trying to shorten the project by compressing non-critical activities. Effective shortening happens only on the critical path.
The critical path governs project duration; compress it, not the rest.
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A schedule is built by arranging activities in a network diagram reflecting their dependencies. The critical path is the network longest path with the least float, which is why it sets the shortest possible duration. When duration must be shortened, choose between crashing by adding resources to critical activities at the least added cost, and fast-tracking by running normally sequential activities in parallel; the first increases cost, the second increases risk and rework. Resource leveling balances loading and may extend duration, while resource smoothing stays within available float without changing the critical path.
Frequently asked questions
What is the critical path?
The longest chain of linked activities, and it determines the project shortest possible duration.
What is float?
How much an activity can be delayed without delaying the project; critical path activities have no float.
What is the difference between crashing and fast-tracking?
Crashing adds resources to critical activities; fast-tracking runs normally sequential activities in parallel.
Which is riskier, crashing or fast-tracking?
Crashing increases cost; fast-tracking increases risk and rework.
What is the difference between resource leveling and smoothing?
Resource leveling balances loading and may extend duration; resource smoothing stays within available float without changing the critical path.
Why compress only the critical path?
Because it alone determines project duration; compressing non-critical activities does not shorten the project.