Planning
Critical Path vs Longest Path
They are often treated as identical. On a constrained programme they diverge — and knowing which delays truly threaten completion depends on telling them apart.
The critical path is the sequence with the least total float. The longest path is the continuous chain of driving activities to completion, traced through each activity’s driving predecessor regardless of float.
Why they diverge
On a clean schedule they coincide. Add hard constraints, multiple calendars or imposed dates, and they separate — float is distorted, and the least-float path may no longer be the chain actually driving the finish.
Why it matters
Entitlement and management attention should follow the work that genuinely drives completion. On a constrained programme, reconciling the critical path against the longest path is how you find it — and how you avoid defending the wrong delays.