Schedule Mechanics & Data
Negative Float
Negative float means an activity's late dates are calculated as earlier than its early dates -- a sign the schedule's own logic already shows the project finishing later than a required or contractual date.
Definition
Total float should never go below zero on a schedule that's forecasting realistically -- a negative value means the network, as currently logic-tied and dated, already projects finishing past a date it's constrained to hit (a contract milestone, a mandatory finish constraint downstream). DCMA's Check 7 targets zero negative-float activities; any negative float found is treated as a genuine, current problem requiring a recovery plan or an accepted schedule slip, not a data-quality issue to simply clean up.
Example
A finish milestone carries a Mandatory Finish constraint tied to a contractual date, and the activities feeding it are now calculated at -9 days of total float -- meaning the network's own math already shows missing that date by 9 days if nothing changes.