Constraints
Date restrictions that override logic — use sparingly.
What it is
Date restrictions placed on activities — Start On or After, Finish On or Before, Mandatory Start/Finish, As Late As Possible, and others.
Why it matters
Constraints override the network logic. Too many — especially hard or mandatory ones — mean the schedule can no longer react to progress, which disables control.
In practice
- Soft constraints (Start On or After) preserve forward logic; hard and mandatory ones break it.
- A Mandatory Finish can hide negative float and mask genuine slippage.
- The DCMA checks flag excessive hard constraints for good reason.
- Every constraint should map to something real — a contractual milestone, an access date, a sectional completion.
Watch for
- A completion date held by a Mandatory Finish rather than logic — it cannot slip even when it should.
- Constraints used to “fix” a messy network instead of correcting the logic.
- Hidden constraints quietly inflating or suppressing float.