Every construction dispute of any size in the GCC will, sooner or later, turn on the evidence of an expert. Delay analysis, quantum valuation, structural causation — these are not questions a tribunal can resolve from the contract alone. It needs someone who can translate programme logic, cost records, and engineering fact into an opinion the tribunal can rely on.
The trouble is that "expert witness" is a role, not a qualification. A quantity surveyor, a delay analyst, and a structural engineer can each hold the title without ever having internalised what the role actually demands. This series sets out what practice excellence looks like for construction and engineering experts working across DIAC arbitration, the DIFC Courts, arbitrateAD proceedings, and FIDIC-based contract disputes throughout the region — starting here with the foundations.
The role is defined by duty, not appointment
An expert witness is not simply a technical adviser who has been asked to write a report. What separates an expert witness from every other consultant on a case is a single, overriding obligation: the duty runs to the tribunal, not to the party paying the fee.
This principle sits at the centre of every serious professional standard governing expert evidence — the IBA Rules on the Taking of Evidence, the CIArb Protocol for the Use of Party-Appointed Expert Witnesses, and RICS's own Practice Statement on surveyors acting as expert witnesses all say some version of the same thing: the expert's evidence must be the independent product of the expert, uninfluenced by who is instructing or paying them, and must cover matters unfavourable to that party's case just as fully as matters that help it.
In practice, this means an expert witness of genuine credibility will:
- Reach the opinion the evidence supports, not the opinion the client wants
- Disclose facts and assumptions that cut against their own conclusion
- Decline instructions that fall outside their expertise, however commercially attractive
- Say so plainly when the evidence does not permit a definitive view
None of this is about being unhelpful to the instructing party. A well-reasoned, independent opinion that survives cross-examination is far more valuable to a client than an advocate's report that collapses under scrutiny. Tribunals in Dubai, Abu Dhabi, and across the wider region have grown increasingly sophisticated in identifying advocacy dressed up as expert evidence — and increasingly willing to discount it accordingly.
Technical competence is the entry ticket, not the differentiator
Genuine subject-matter expertise is a precondition, not a distinguishing feature. On a delay claim tied to a rail or transport infrastructure project, or a quantum dispute on a solar PV programme, the tribunal expects an expert who understands the engineering and commercial reality of that sector — not a generalist applying a template.
What actually distinguishes a strong expert from an adequate one is:
- Methodological rigour. A delay analysis that names its method (as-planned versus as-built, time impact analysis, windows analysis) and applies it consistently is far more defensible than one that shifts approach to suit the answer.
- Clarity under pressure. Written reports must withstand written questions and expert-to-expert meetings; oral evidence must withstand cross-examination. Experts who can explain a complex quantum build-up in plain terms, without retreating into jargon, tend to carry more weight with tribunals.
- Consistency across the file. Opinions given in a report, in a joint statement with the opposing expert, and under cross-examination must all tell the same story. Any daylight between them is where cross-examining counsel will go first.
Why this matters more, not less, in the GCC context
The GCC's dispute resolution landscape has matured rapidly. DIAC's 2022 Rules brought procedural modernisation broadly in line with international institutions. The DIFC Courts, including the Technology and Construction Division, apply common-law-influenced procedure with rigorous expert evidence requirements. arbitrateAD, which replaced ADCCAC in February 2024, has positioned Abu Dhabi as a serious seat for construction and infrastructure disputes. Against this backdrop, tribunals and counsel alike expect expert evidence that meets international standards, not merely regional convention.
For lawyers instructing experts, this means credibility checks should start well before a report is drafted — at the point of selecting and briefing the expert. For contractors and engineering businesses facing a dispute, it means understanding that the expert's job is not to advocate for you, but to give the tribunal a reason to trust the numbers. For private clients navigating a construction dispute for the first time, it means knowing that an expert's independence is a protection, not an obstacle — a report that only tells you what you want to hear is a report a tribunal will not believe.
The remaining parts of this series work through what practice excellence looks like at each stage of an expert's engagement: accepting instructions, managing conflicts, inspecting the works, structuring a defensible report, and standing behind that opinion under cross-examination. Together they set out a practical standard against which any construction or engineering expert witness — and any lawyer instructing one — can measure the work.
This article is part of a 20-part series on construction and engineering expert witness practice in the GCC. Part 2 examines the overriding duty to the tribunal in more detail, including how it applies specifically within DIAC and DIFC proceedings.