FIDIC

Disruption Claims Under FIDIC — The Measured Mile Methodology

When late information, multiple variations, or forced resequencing reduce the contractor’s productivity, the cost of that loss is recoverable under FIDIC Clause 20.2 — but only with rigorous methodology and contemporaneous evidence.

7 min read · Updated 23/05/2026

In this article

1. The Distinction Between Delay and Disruption
2. Measured Mile — The Preferred Methodology
3. Establishing the Reference Period
4. Contemporaneous Production Records
5. Alternative Methods Where No Measured Mile Exists
6. Presenting and Defending Disruption Claims

Key takeaway

Disruption claims succeed when the contractor demonstrates the actual productivity rate during an undisrupted period (the measured mile), compares it against the disrupted period, isolates the employer-caused cause, and quantifies the cost of the loss. Without contemporaneous production records, the claim is vulnerable to rejection.

1. The Distinction Between Delay and Disruption

Delay is about time: the work is performed later than planned, and the completion date is pushed forward. The cost of delay is prolongation — the extended site overhead, supervision, and head office cost.

Disruption is about efficiency: the work is performed, but at a lower productivity rate than planned, resulting in higher cost per unit of output. A team that was expected to install 50 panels per week installs only 35 per week due to late design information, multiple instruction sequences, or access constraints. The cost of disruption is the additional cost of achieving the same output at the lower productivity rate.

Many FIDIC projects suffer both: delay (pushing the completion date forward) and disruption (increasing the cost rate of work performed). Understanding the distinction is critical because the quantification methodology differs for each.

2. Measured Mile — The Preferred Methodology

The measured mile is the gold standard for disruption quantification. It is the contractor’s actual performance rate on undisrupted work, used as a benchmark against which the disrupted work is measured.

The principle: if the contractor achieved a specific productivity rate during an undisrupted period on the same project (the same work, the same crew, the same site conditions), that rate is the most reliable evidence of what the contractor should have achieved in the disrupted period, absent the disruption.

Example: The contractor installs structural steel on a multi-storey building. During Phase 1 (months 1–3), when design information was complete and site access was unrestricted, the crew installed 40 tonnes per week. During Phase 2 (months 4–6), when the design was being re-issued to incorporate changes and site access was restricted, the same crew installed only 28 tonnes per week. The productivity loss is 12 tonnes per week. If the cost per tonne installed (labour, supervision, plant) is known, the additional cost can be calculated directly: 12 tonnes × cost per tonne × number of weeks = disruption cost.

Why the Measured Mile Works

The measured mile avoids the most common weakness in disruption claims: reliance on the tender estimate. Tender estimates for productivity are conservative — contractors quote conservatively to protect themselves. They often assume lower productivity than is actually achievable, to provide a margin of safety. Using the tender estimate as a benchmark against actual disrupted period performance will underestimate the claim.

The measured mile overcomes this by using the contractor’s own actual performance as the benchmark. This is why it is preferred by arbitration tribunals and by the Society of Construction Law Delay and Disruption Protocol (2nd edition, 2017).

3. Establishing the Reference Period

For the measured mile to be valid, three conditions must be satisfied: (1) the reference period must be genuinely undisrupted — work performed under the conditions and circumstances contemplated by the contract, without the employer-caused event that caused the disruption; (2) the work must be of the same or substantially similar character — same trade, similar scale, similar site conditions; (3) the period must provide sufficient data to establish a reliable baseline — a single day of installation is not sufficient; multiple weeks of consistent performance are needed.

The reference period may be before the disruption (early project work), or it may be after the disruption (if the disrupting event was temporary). It may even be from a different but comparable project by the same contractor, though on-project measurements are strongly preferred.

Variables to Account For

4. Contemporaneous Production Records

The measured mile stands or falls on production records. These must be created during the work — not reconstructed after the fact. The relevant records include:

• Daily site diaries — signed by the site supervisor, recording what work was performed, by whom, and for how long
• Gang productivity sheets — recording the number of workers deployed, the hours worked, and the output achieved (tonnes installed, linear metres laid, units completed)
• Photographs and video — showing the state of the work at various points, with dated metadata
• Delivery dockets and material receipts — recording when materials arrived on site, when they were used
• Timesheets and labour records — showing who was deployed, when, and for how long
• Meeting minutes — recording site instructions, approvals, delays, and any disruptions identified in real time

These contemporaneous records create the as-built programme and the production baseline from which the measured mile is derived. Without them, the disruption claim lacks evidentiary foundation.

5. Alternative Methods Where No Measured Mile Exists

If no undisrupted period exists on the same project (because the entire scope was affected, or because the project started in disrupted conditions), alternative benchmarks may be used:

Industry Productivity Standards

Standards such as those published by AACE International (formerly the Association for the Advancement of Cost Engineering), the Royal Institution of Chartered Surveyors (RICS), or equipment manufacturers, provide published productivity benchmarks for standard trades. These are weaker than a project-specific measured mile — tribunals prefer actual project performance over industry standards — but they are admissible when no alternative exists.

Contractor’s Historical Performance

If the contractor has performance data from previous projects of similar character, this may be used as a comparative benchmark. Again, this is weaker than a project-specific measured mile, and the comparability of the projects must be carefully established.

Expert Assessment

Where neither a measured mile nor industry benchmarks are available, an expert quantity surveyor or delay analyst may be instructed to assess what the contractor would reasonably have achieved absent the disruption, based on the crew composition, site conditions, and the nature of the work. This is the most uncertain methodology and will be tested rigorously by the employer’s expert.

6. Presenting and Defending Disruption Claims

When presenting a disruption claim under FIDIC Clause 20.2, the contractor must demonstrate: (1) the qualifying event that caused the disruption; (2) the effect on productivity (with measured mile or alternative benchmark); (3) the financial cost of the lost productivity; (4) the causation between the event and the loss; and (5) that the loss was not avoidable through reasonable care and mitigation.

The claim should be presented with a programme-based analysis showing where the disruption occurred in the project schedule, which activities were affected, and how the productivity loss translated into cost impact. This requires a collaborative analysis from the contractor’s cost engineer, delay analyst, and quantity surveyor.

Preparing a Disruption Claim Under FIDIC?

Disruption claims require a measured mile analysis, expert productivity assessment, and rigorous cost quantification. We advise at the notice stage, during claim development, and through settlement or arbitration.

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