Schedule Mechanics & Data
Out-of-Sequence Progress
Out-of-sequence progress is when an activity is reported as started or complete before its predecessor's logic says it should be possible -- a sign the schedule's logic doesn't match how the work actually happened.
Definition
CPM logic assumes work proceeds in the order the network dictates: an activity's predecessors finish (or reach the point their relationship type requires) before it starts. When field progress is reported against activities in a different order -- a successor starting while its Finish-to-Start predecessor is still incomplete -- the schedule either has to recalculate around that inconsistency in a way that can produce misleading dates, or the logic itself needs correcting to reflect how the sequence genuinely works. Frequent out-of-sequence progress across a schedule is often a sign that the original logic was built without close enough coordination with how the trades actually intended to execute the work.
Example
MEP rough-in is reported 30% complete while its Finish-to-Start predecessor, wall framing, still shows only 80% complete -- work that, per the schedule's own logic, shouldn't have been able to start yet.