A Delay Analysis Review of Santos Limited v Fluor Australia
In Santos Limited v Fluor Australia Pty Ltd [2025] QSC 184, the Supreme Court of Queensland provides one of the clearest recent judicial statements on construction delay expert analysis.
The judgment is particularly relevant to delay analysts and expert witnesses because it shows that courts scrutinise methodology and reasoning as closely as the conclusions reached.
For organisations that specialise in delay analysis, the decision highlights the following:
Decision makers generally place greater weight on transparent reasoning and contemporaneous evidence than on complex models or software-generated outputs that are not clearly supported by the project record.
Differing Expert Opinions
Both parties retained delay experts who adopted an agreed baseline methodology: an as-planned versus as-built windows analysis. Their opinions diverged, however, when one expert introduced “but-for” scenarios into the assessment.
The claimant’s expert applied an as-planned versus as-built windows analysis, comparing the planned programme with the contemporaneous record of events on site. The analysis divided the project into discrete time periods and identified how critical-path delay accumulated over time.
The defendant’s expert contended that, even in the absence of certain delay events, the project would have completed late because other activities were near critical.
The Court preferred the claimant’s approach. It found the claimant’s expert evidence to be “consistent with the objective factual circumstances and, indeed, was supported by a prodigiously detailed analysis of background facts and documents. It was unshaken in cross-examination”.
Justice Freeburn addressed the near-critical path analysis advanced by the defendant’s expert, concluding that the evidence did not establish that any near-critical delays in fact became critical. His Honour observed that the “process of identifying the critical path, that is what is controlling the progress, is fundamental to the agreed process”.
Limitations of Near-Critical Path Reasoning
The defendant’s expert relied on a ‘but-for’ scenario, which proceeded on the following proposition:
“If this delay had not occurred, another event would have caused delay in any case.”
The difficulty with this proposition is that construction projects are highly dynamic. Removing one delay event can alter sequencing and logic, change the order in which activities are performed, or shift criticality to different activities. Accordingly, delay opinions should be grounded in contemporaneous facts and records, rather than hypotheses about what might have occurred under different conditions.
The Court accepted that it is not safe to assume the project would have been late in any event without evidence demonstrating what would, on the balance of probabilities, have occurred. Delay analysis should reflect how projects operate in practice, rather than how they might operate in theory.
Importance of Analysing Actual Progress
The claimant’s expert focused on actual progress and identified:
What the planned intent of the parties was.
What happened contemporaneously.
How specific issues affected progress and contributed to critical delay to completion.
By assessing progress at regular intervals, the expert identified the critical path and demonstrated delay by reference to as-built site records. This approach produced a clear causal narrative that could be followed and tested against the contemporaneous documentation.
The Court characterised this as a sensible and reliable approach to establishing cause and effect, noting that the analysis “is actually derived from a detailed analysis of the facts and documents of the project”.
More broadly, analyses anchored in observed progress are generally more persuasive than analyses based on counterfactual scenarios or overly complex software modelling that is not transparently linked to the project record.
Best Practice
The defendant submitted that the referees preferred an approach that aligned with guidance in the Society of Construction Law Delay and Disruption Protocol. It argued that, because the Protocol was not incorporated into the contract, it should not be relied upon.
The Court agreed that the Protocol is not legally binding. It provides guidance on how delay analysis may be undertaken appropriately. While Justice Freeburn noted that “the SCL Protocol is not a straitjacket…”, adherence to its principles can demonstrate alignment with accepted industry practice.
Justice Freeburn added that “the referees were uncomfortable with the logic of (the defendant’s expert’s) departure from the agreed SCL Protocol methodology”. The decision confirms that, while the Protocol does not have the force of law, it may operate as a practical benchmark for professional practice.
Comparable Australian Authorities
A similar emphasis on evidence-led reasoning appears in White Constructions Pty Ltd v PBS Holdings Pty Ltd [2019] NSWSC 1166, where the Supreme Court of New South Wales was critical of delay opinions that were insufficiently anchored to direct evidence of what occurred on the project. The decision is commonly cited for the proposition that an expert’s programming methodology is not, of itself, a substitute for proof of causation and the actual impact of the alleged delay event.
Courts have also assessed delay expert methodology by reference to recognised analytical frameworks. For example, in Alstom Ltd v Yokogawa Australia Pty Ltd (No 7) (2012) (Supreme Court of South Australia), the Court rejected a delay methodology for reasons including that it was not recognised by the Society of Construction Law Delay and Disruption Protocol (or other established reference texts). While the Protocol does not have contractual force, Australian decisions of this kind illustrate how it may operate as a practical benchmark when assessing whether an expert’s approach is orthodox and reliable.
Depending on contract wording, Australian courts have also accepted that delay and extension-of-time assessments may be undertaken prospectively or retrospectively. In Built Qld Pty Ltd v Pro-Invest Hospitality Opportunity (ST) Pty Ltd [2021] QSC 224, the Supreme Court of Queensland considered extension-of-time provisions based on Australian Standard forms and confirmed that the assessment may accommodate either approach, reinforcing that the selected method should be fit for purpose and supported records.
Evidence Over Speculation
The referees concluded that one party had demonstrated how the relevant breaches caused delay, whereas the other had not established a credible alternative explanation. The Court accepted that assessment.
This reflects the following principle:
Delay analysis is not an exercise in speculation; it requires proof of what occurred, supported by contemporaneous records. Where an expert cannot link delay events to observed site activities and reliable documentation, the evidence is less likely to be accepted or afforded significant weight by the tribunal.
Records
A key lesson from the decision is the critical role of record-keeping in construction projects. Delay analysis is only as robust as the evidence supporting it. Contemporaneous records, such as programmes, progress reports, site diaries, photographs, and meeting minutes enable an expert to establish what occurred and when.
Without reliable records, delay analysis may become speculative and assumption-based, which courts and tribunals are unlikely to accept. Proper record-keeping therefore underpins the ability to demonstrate cause and effect, strengthens the credibility of expert evidence, and improves a party’s prospects of success in delay-related disputes.
Key Outcomes
Santos Limited v Fluor Australia Pty Ltd [2025] QSC 184 demonstrates that delay analysis is not solely a technical exercise; it also requires sound judgment and clear communication.
An effective delay expert should:
Apply a clear methodology that can be understood by the tribunal and the parties.
Explain how specific delay events affected the critical path, supported by contemporaneous as-built records.
Follow recognised guidance appropriately, and avoid speculation and unsupported assumptions.
In summary, an effective delay expert combines technical capability with practical construction experience and clear, evidence-led reasoning.
At Accura Consulting, our team of experts work with clients to create a tailored solution to problems. If you have an issue and want expert support, get in touch.
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