Delay is late completion. Disruption is lost productivity. They are proved from different evidence, by different methods, and conflating them is the fastest way to lose both.
The two claims are not the same argument.
A delay claim asks whether the completion date moved and who caused it. It is answered on the critical path: an event that does not affect the critical path does not delay completion, however disruptive it was on site.
A disruption claim asks whether the work cost more to perform than it should have, whether or not completion moved at all. It is answered on productivity, and it can succeed on a project that finished on time.
The Society of Construction Law Delay and Disruption Protocol treats them separately for this reason. Pleading them as one claim usually means the disruption case is being run on delay evidence, which does not prove it.
The analysis follows the record, not the theory.
AACE International RP 29R-03 sets out the recognized forensic schedule methods. Which one applies is a function of the records that exist.
Establish the baseline
Identify the accepted schedule and confirm it was logically sound before any delay event.
Build the as-built
Reconstruct what actually happened from contemporaneous records rather than from the final schedule update.
Identify the critical path
Establish the path driving completion, and how it moved between updates.
Window the analysis
Divide the project into periods and analyze each against the schedule current at the time.
Attribute cause
Tie each period of critical delay to a specific event and a contractual entitlement route.
Separate disruption
Take productivity loss out of the delay case and prove it on its own evidence.
What the argument is built from.
Every conclusion has to be traceable to a document that existed at the time.
Where these claims fail.
Almost never on the merits of the event. Usually on how the case was built.
The baseline was never sound
A schedule with open ends, negative lag, or constraints masking float will not support any analysis run on it.
The as-built is the last update
Final updates are often reconstructed after the fact. If the as-built cannot be sourced to contemporaneous records, it is an assertion.
The method does not match the records
A time impact analysis run on a project with no reliable updates is a modelling exercise, not evidence.
Disruption is inferred from delay
Productivity loss claimed as a consequence of delay, with no measured productivity evidence, generally fails.
What the Matter Model does with it.
It reconstructs the as-built from the contemporaneous record rather than from the final update, and holds every activity date against the document that evidences it.
It keeps the critical path tied to the events and records said to drive it, so a change in one issue shows up across the schedule, the entitlement, and the damages at the same time.
Standards and authorities
- SCL Delay and Disruption Protocol, 2nd edition (February 2017)
- AACE International RP 29R-03, Forensic Schedule Analysis
General reference on how these disputes are argued. Not legal advice, and not a statement of the law of every jurisdiction or seat.
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