In the normal course of executing a project, Change Orders (that is changes to the
contractual scope of work) often arise. These may be initiated by either the Company/
Client or the Contractor.
2. Methodology (or How to Numerically Prove Schedule Impacts)
One must be aware that supporting any statement in a claim environment is extremely
hard. Qualitative statements are simply difficult to defend due to their very subjective
nature, open to interpretation and impossible to quantify with accuracy.
The only way to satisfy any enquirer is to establish the claim numerically. And how
is that done in the case of a schedule claim? How do we go about quantitatively establishing
the number of days a schedule was impacted (positively or negatively)?
Via the comparison of Critical Path Method (CPM) schedules. It's very simple: you
have a baseline CPM schedule (basically a proper schedule of the original execution
plan with all the activities tied up with predecessor and successor activities) and
compare it to a copy of this baseline schedule with the new scope of work (additional
and/ or removed activities).
The difference between completion dates of the original CPM schedule versus the schedule
which includes the Change Order scope of work is the number of days that may be claimed.
Simple arithmetic. Extension of Time Claim = BL Schedule Completion Date - Revised
Schedule Completion Date
3. Notes (or How to Avoid a Recursive Argument)
Some notes for the unwary planner: If a change in scope does not impact the critical
path of the schedule then no claim can be made (that is the revised CPM schedule
does not have a different completion date than the original baseline schedule).
The above is true keeping all constants the same. If the change resulted in an extended
duration and subsequently this was "crashed" (durations were made shorter) to maintain
the original schedule completion date, then additional compensation may be requested
for additional financial compensation. Examples of this would be the air-freight
of critical materials instead of sea-freight, or the use of overtime.