Expert Evidence vs Industry Experience in Construction Disputes

What Courts Expect from Quantum, Delay, and Disruption Claims

Introduction

In complex construction disputes, outcomes are often determined not by the volume of material presented, but by the quality and structure of expert evidence. A recurring issue in litigation and arbitration is whether opinions based primarily on industry experience can carry the same evidential weight as opinions grounded in structured expert analysis.

The recent decision in Santos Limited v Fluor Australia Pty Ltd & Fluor Corporation [2025] QSC 184 provides a clear and timely illustration of how courts approach this distinction. While the dispute involved claims relating to delay, disruption, and quantum, the judgment is particularly instructive on a more fundamental issue: what qualifies as admissible and persuasive expert evidence.

This article examines:

• the distinction between expert evidence and industry experience,

• how courts assess competing expert opinions, and

• the standard of explanation and transparency expected from experts in construction disputes.

The Role of Expert Evidence in Construction Disputes

Construction disputes frequently involve issues that lie outside the ordinary knowledge of courts and tribunals. Delay analysis, productivity loss, and quantum assessment require specialised technical expertise. For this reason, expert evidence plays a central role in assisting decision-makers.

However, courts have consistently emphasised that an expert’s function is not to advocate, but to explain technical matters through reasoned analysis. The value of expert evidence lies not in the expert’s résumé alone, but in the methodology, assumptions, and reasoning by which conclusions are reached.

Industry Experience Is Not, by Itself, Evidence

A key issue in Santos v Fluor was the contrast between two different approaches to evidence.

One party advanced its claims through structured expert analyses, including detailed quantum assessments that:

• identified the relevant cost categories,

• linked those costs to specific project activities and events,

• relied on contemporaneous project records, and

• explained the analytical steps leading to the claimed amounts.

The opposing party, by contrast, relied heavily on opinions from individuals with substantial construction experience, but who had not been appointed as experts and whose reports largely consisted of experience-based critiques of the other party’s expert evidence.

The Court drew a clear distinction between these approaches. While acknowledging the value of industry experience, it reaffirmed that experience alone does not constitute evidence. Without an articulated analytical framework, experience remains opinion, not proof.

The Requirement to Explain Assumptions and Reasoning

A central theme of the judgment is the court’s insistence on transparency of reasoning. The Court reiterated that expert opinions must expose their foundations to scrutiny:

“The facts upon which an expert’s opinion is based must be available for scrutiny by the tribunal. A court can hardly be expected to act upon an opinion the basis for which is not explained.” ([259])

This principle applies equally to quantum, delay, and disruption evidence. An expert must:

• identify the factual material relied upon,

• disclose the assumptions made,

• explain why those assumptions are reasonable, and

• demonstrate how the conclusion logically follows from the facts.

Opinions that do not reveal this reasoning process are vulnerable to being given little or no weight, regardless of the experience of the person expressing them.

Methodology Matters More Than Labels

The judgment also underscores that courts are not concerned with whether an expert adopts a particular branded methodology. What matters is whether the methodology used is:

• internally coherent,

• consistent with the available records, and

• capable of being tested and challenged.

Expert reports prepared with clarity, analytical rigour, and alignment with recognised standards tend to carry significantly greater weight. In international construction disputes, reference frameworks such as the Society of Construction Law (SCL) Protocols and EWI guidelines often provide useful benchmarks against which the discipline and transparency of expert reasoning can be assessed.

Conversely, methodologies that depart from accepted practice, or that fail to disclose their underlying logic and assumptions, risk being discounted entirely. The issue is not the sophistication of the model, but whether the tribunal can understand, test, and evaluate the reasoning that leads from fact to opinion.

Practical Implications for Parties and Experts

The implications of Santos v Fluor extend beyond the specific facts of the case. For parties advancing construction claims, the decision reinforces that:

• expert evidence must be built on demonstrable analysis, not generalised experience, and

• criticism of opposing expert evidence must engage with the underlying reasoning, not merely assert alternative views.

For experts, the judgment is a reminder that:

• professional experience must be translated into a structured, explainable methodology, and

• credibility before a court or tribunal is earned through transparency, not authority alone.

Conclusion

*Santos Limited v Fluor Australia Pty Ltd & Fluor Corporation* confirms a principle that has long underpinned construction disputes but is now articulated with renewed clarity: courts cannot act on opinions that are not explained.

Industry experience remains valuable, but it is not evidence unless it is expressed through disciplined analysis, disclosed assumptions, and a clear chain of reasoning. In construction disputes involving delay, disruption, and quantum, the decisive factor is not who has built the most projects, but whose evidence can withstand scrutiny.