V601 Developments v Probuild confirms that delay and disruption must be proven independently. Disruption techniques can suggest loss, but only a forensic QS and quantum expert can show cause and cost with evidence. 

For quantum experts, CPB Contractors v Transport for NSW completes the progression from Kvaerner to Probuild. It confirms that inefficiency is not a separate claim. It is the cost consequence of change. 

In construction claims, delay and disruption are different things. Delay is about time. Disruption is about cost. The two demand different evidence from experienced quantum expert witness and delay expert witness. 

The case of John Holland Construction & Engineering Pty Ltd v Kvaerner R J Brown Pty Ltd remains one of the earliest and most important Australian warnings against “rolled-up” or “global” claims for quantum experts to consider.

The decision in Santos Limited v Fluor Australia Pty Ltd does more than explain what disruption is. It shows, in practical terms, how a disruption claim must be analysed and proven. 

Experience isn't evidence. Santos v Fluor shows why an effective quantum expert witness needs more than industry experience. Courts expect transparent methodology, construction costing expertise and evidence that withstands scrutiny.

The decisions in A.M.O. Rifat Holdings Pty Ltd v Dib is likely to become an important authority on quantum meruit and the Court’s treatment of the evidence. For expert quantity surveyors the judgment demonstrates what good valuation evidence looks like.

By the time cross-examination starts, it's too late to fix a weak methodology. The discipline has to be built into the report from the first draft: causation traced event by event, assumptions labelled as assumptions, and so on.

The work of a quantum expert witness sits at the intersection of quantity surveying, contract law, and forensic investigation, and the experts who do it well are fluent in all three.

On most large projects, delay and disruption get bundled together. But they are not the same thing. Delay impacts the critical path. Disruption affects how work is carried out.

The decision in Alexanderson Earthmover Pty Ltd v Civil Mining & Construction Pty Ltd is a reminder that many standby and productivity claims fail before evidence is tested.

In Amey LG v Cumbria County Council, the Court did not reject the measured mile but it stripped it of the mystique that some experts trade on. This UK case is essential reading for quantum experts and quantity surveyors.

Abigroup vs Sydney Catchment shows how courts assess expert reasoning, and why conclusions must be supported by an exposed logical process. For expert Quantity Surveyors, those points go to the heart of credible evidence. 

Delay claims do not always fail on time, they fail on money. That is the lesson of Walton Construction Pty Ltd v Illawarra Hotel Company Pty Ltd. Walton succeeded on extensions of time but the referee’s approach to delay costs was rejected

Expert evidence in construction disputes is not assessed only by weight. If the foundation for expertise is not properly established, the evidence may never be considered at all as the decision in Dura Constructions v Hue Boutique Living reminds us.

Producing expert quantum reports is often written about in the abstract. Reports should be rigorous. Costings should be substantiated. Methodology should be demonstrable and defensible.

The Court’s decision in Santos v Fluor is a timely reminder that expert evidence on quantum must do more than state conclusions. It must explain, transparently and logically, how those conclusions are reached. 

A forensic quantity surveyor review of how courts engage with expert quantity surveying evidence when liability is no longer the real issue and instead it is how to value rectification works where competent experts disagree on scope and cost. 

A forensic quantity surveyor can analyse and assess, but the court decides outcome and there’s a difference between opinion and proof. Forensic QSs must present reliable evidence that enables the court to make that decision with confidence. 

A quantum expert review of why Built Environs v Perth Airport is a clear modern illustration of why drawing deficiency and disruption claims often fail before they ever reach trial.