Choosing the Right Quantum Expert: The Court’s Message in Santos v Fluor
The Supreme Court of Queensland’s decision in Santos Limited v Fluor Australia Pty Ltd [2025] QSC 184 provides a clear reminder of why quantum evidence must be given by someone trained and qualified in quantity surveying.
The referees and the Court compared two opposing quantum experts. One was a Chartered Quantity Surveyor, experienced and qualified in the measurement, valuation and assessment of construction costs. The other was an accountant, skilled in financial analysis but not experienced or qualified as a Quantity Surveyor.
The outcome was decisive. The referees and the Court preferred the Quantity Surveyor’s evidence on almost every issue, finding the accountant’s reasoning “deeply flawed” and often outside his field of expertise. All parties are anonymised but the process is real.
When a Non-QS Tries to Do QS Work
The case shows what happens when an expert without construction cost training attempts to give quantum evidence. The accountant’s approach was not only less persuasive it was technically unsound.
1. Misclassification of Costs
He classified all Field Mechanical Installation costs as direct costs because they appeared under that heading in payment claims. Fluor’s own records showed that about two-thirds were indirect. The referees said this was “deeply flawed” and ignored both the company’s cost data and the expert’s own criteria.
Lesson: Quantity Surveyors understand how costs behave on site and test classifications against real project evidence. Cost codes are not cost truth.
2. Ignoring Project Structure
He treated four separate subcontracts as one, assuming all time-related costs were activity-specific. The referees said this was unrealistic and contrary to how the project was actually delivered.
Lesson: Analysis must follow the real structure of the works. A QS knows how preliminaries, supervision and overheads spread across packages.
3. Undefined and Subjective Language
He used vague terms such as “significant” and “disproportionate” without any benchmark or calculation. The referees said those words were “adjectival” and “devoid of any substantive significance.”
Lesson: QS evidence must be measurable. Every conclusion must be backed by evidence, computations and data.
4. Inconsistent Application of Principles
He defined direct and indirect costs correctly in his report but contradicted his own definitions during cross-examination. The referees said he failed to apply his method consistently.
Lesson: Consistency is credibility. Once definitions are set, they must be applied throughout the analysis.
5. No Analytical Verification
He criticised the opposing expert’s man-hour calculations but did not carry out his own count or calculation. The referees said he had raised “hypothetical concerns” and performed no real analysis.
Lesson: A QS verifies through measurement. Criticism without computation is speculation, not evidence.
6. Beyond His Field of Expertise
The Court stated that the accountant’s “qualifications and experience, as an accountant experienced in the analysis of claims, did not enable him to make an assessment of proportionality,” noting that such judgments “would ordinarily require engineering or related construction experience.”
Lesson: This is the key point. The Court found he was not experienced or qualified as a Quantity Surveyor, and therefore not equipped to assess construction costs in a forensic context.
Why the Quantity Surveyor Was Preferred
The referees described the Quantity Surveyor as “an impressive witness who did his best to give accurate evidence.” He corrected himself when shown contrary material and based his conclusions on project records.
The Court found that the work he undertook was “well within his experience, qualifications and expertise” and that “he was primarily a Quantity Surveyor.” His reasoning was consistent, logical and aligned with construction practice.
Lessons for Solicitors and Clients
This case is a warning for those who instruct experts in construction disputes.
When appointing a quantum expert, ensure they are experienced and qualified as a Quantity Surveyor. Accountants and financial analysts may understand numbers, but they do not necessarily understand how construction costs behave, how productivity changes on site, or how overheads flow through a project.
The Court’s message is clear. Forensic quantum evidence is a specialist discipline within quantity surveying. Using someone without that foundation risks analytical error, loss of credibility and rejection of their evidence.
Conclusion: disruption framed as change
Santos v Fluor stands as a practical reminder for experts, solicitors and clients alike:
Use a QS to do QS work.
In quantum matters, qualifications and discipline matter. Credibility before the Court depends on appointing an expert who truly understands how construction costs are measured, analysed and evidenced.
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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