Why V601 and White Constructions Matter to Quantum Experts and Quantity Surveyors
Two Australian cases have reshaped how tribunals view expert evidence in delay and quantum disputes.
V601 Developments v Probuild and White Constructions v PBS may have turned on issues of delay, but their wider message is about how experts prove cause, value and entitlement. They set a clear benchmark for how quantum experts (quantity surveyors) must present evidence today.
1. Causation drives value
Both judgments made one point impossible to ignore: no cause, no cost. Justice Digby and Justice Hammerschlag each focused on factual causation. They wanted to see what happened, why it happened and how it affected completion.
The evidence had to show a clear and logical chain of cause and effect, not inference or assumption. This is where credibility begins linking cost directly to cause.
2. Facts before formula
Both judges rejected analyses that looked refined but were detached from the project record.
Complex models, productivity ratios and theoretical rates carry little weight unless they align with contemporaneous evidence such as timesheets, diaries, procurement logs and cost data.
A valuation that cannot be tested against project facts adds little value. What matters is not how it looks, but whether it stands up to evidence.
3. Logic a tribunal can follow
In both cases the tribunals valued reasoning that was clear and traceable. They were not persuaded by jargon or density.
The same applies to quantum analysis. The expert who explains each step in plain language is more persuasive than one who hides behind complex formulas, graphs and theory.
A strong report reads like a clear narrative, what happened, what it cost and how that figure was computed. It is not about simplicity for its own sake, but about reasoning that can be followed, tested and trusted.
4. Clarity over complexity
These decisions favour experts who communicate with precision.
Complexity can cloud judgment, but clarity builds confidence. The expert who presents well-structured, evidence-based reasoning gives the tribunal something it can rely on.
Forensic work is not about impressing the reader. It is about helping the tribunal reach a conclusion based on facts that stand up under scrutiny.
The message for lawyers
For lawyers, these cases change how expert evidence should be used. They show that the value of an expert is not in the method chosen but in the strength of the evidence behind it.
A credible expert does not just calculate; they reason. They connect cost to cause and cause to fact. When that link is proven, the evidence becomes powerful and persuasive.
Both V601 and White Constructions mark a shift toward precision, discipline and factual proof. They set the tone for what modern tribunals now expect from expert evidence.
In summary
Tribunals now expect delay and quantum experts to build their opinions on fact, logic and clarity.
For quantum experts, this is both the challenge and the opportunity. It is what separates the analysts from the true experts.
As both judges made clear, delay and cost are not matters of opinion. They are matters of fact and fact decides outcomes.
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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