Quantum
The measured mile and comparability
The measured mile is the strongest productivity method available, and it is only as strong as the comparability of the two periods being compared.
- Jurisdiction
- General method guidance
- Law and editions as at
- 3 August 2026
- Last reviewed
- 3 August 2026
- Editorial status
- Editorial draft, not yet independently reviewed
The method
Identify a period or area of the same work that was not affected by the events. Measure its productivity as output per unit of input. Measure the impacted period the same way. The difference, applied to the impacted quantities, gives the lost hours. Because both figures come from the project itself, the tender estimate never enters the calculation.
The comparability tests
- Same or genuinely similar scope and specification.
- Comparable crew composition, skill and supervision.
- Similar location, height, access and congestion.
- Similar weather, shift pattern and hours.
- Learning curve accounted for, so early work is not compared with mature production.
- Quantities large enough that the comparison is not driven by a handful of days.
The variants
- Project-specific measured mile, where a genuinely comparable unimpacted period exists.
- Modified measured mile, adjusting for known differences, with every adjustment exposed.
- Comparable crew or area comparison, where the unimpacted work is elsewhere on the same project.
- Earned value, work sampling or production studies, where measurement bases are stable.
- Contemporaneous estimates or industry studies, used as corroboration and adjusted to the project.
The honest failure mode
Selecting the most productive period on the job as the mile, and calling everything below it disruption. That is not a measured mile, it is a benchmark against best performance, and it will be dismantled by anybody who looks at the underlying data.
Where the record comes in
Every mechanism on this page turns on evidence: what happened, what was known and when. A record built as the job happens is worth more than any argument assembled afterwards. Construction Metric keeps that record automatically, from the messages, photographs and voice notes a site team already sends.
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Do not overread this page
Method hierarchies are technical guidance, not a legal ranking. A tribunal decides what it finds reliable on the evidence before it.
General explanation of how contract mechanisms, analysis methods and legal principles generally work. It is not legal or contractual advice, not an opinion on any project, and no standard-form contract wording is reproduced anywhere on this site. Standard forms are routinely amended, so every default described here, including every time period, can be different on your project. Your executed contract, as amended, and the governing law and forum always control. Deadlines may already be running: if an event has occurred, preserve your position and take qualified advice.