Disruption is the hardest claim in construction to prove, because the evidence that would establish it is rarely kept for that purpose.
Measured mile, and everything after it.
The measured mile compares productivity in an unimpacted period against productivity in an impacted period on the same project, with the same workforce and the same work type. It is the preferred method because it uses the project as its own control.
Where no clean period exists, the alternatives are weaker and known to be: earned value analysis, comparison against a properly matched project, or published industry factors such as the mechanical and electrical contractor studies.
Total cost claims, taking the overrun and attributing it to the employer, are treated with suspicion in every jurisdiction. Modified total cost claims improve on that only if the adjustments are genuinely made.
Causes have to be pleaded specifically: trade stacking, out-of-sequence working, extended overtime and the fatigue that follows, repeated remobilization, learning curve loss on repetitive work, rework.
How disruption is proved.
The method is chosen by the records, and the choice has to be defensible.
Find an unimpacted period
Identify a period of the same work performed without the disruptive events.
Normalize the comparison
Match work type, crew composition, location, and conditions.
Measure both periods
Establish output per labor hour in each from contemporaneous records.
Attribute the difference
Tie the productivity gap to specific pleaded events, not to the overrun.
Test the alternative
Where no clean period exists, state plainly why, and why the fallback is reliable.
What the argument is built from.
Almost all of it is labor records, and almost none of it was kept for a claim.
Where these claims fail.
Disruption claims fail more often than any other head.
No unimpacted period is identified
Without a baseline of achievable productivity there is nothing to measure loss against.
The comparison is not like for like
Different work, different crew, or different conditions defeats the measured mile before quantum is reached.
The claim is a total cost claim in substance
Presenting the overrun and calling it disruption puts the burden of disproof on the wrong party, and tribunals notice.
Causes are pleaded generically
Disruption attributed to the employer at large, rather than to specific events, fails on causation.
What the Matter Model does with it.
It quantifies disruption with measured-mile and earned-value evidence the record actually supports, and marks where it does not.
Where the records will not carry a measured mile, it says so rather than substituting a formula and presenting it as measurement.
Standards and authorities
- SCL Delay and Disruption Protocol, 2nd edition (February 2017), Part C on disruption
- AACE International RP 25R-03, Estimating Lost Labor Productivity
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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