Construction and engineering experts working across international arbitration in the GCC operate under the shadow-sm of several overlapping professional standards, none of which is universally mandatory in every forum, and none of which is entirely identical to the others in its detail. This piece sets out how the CIArb Protocol for Party-Appointed Expert Witnesses, the RICS Practice Statement on surveyors acting as expert witnesses, and the IBA Rules on the Taking of Evidence in International Arbitration relate to each other, and how a practitioner should navigate them where they do not perfectly align.
Why multiple standards exist in the first place
Each of these frameworks originates from a different source and serves a distinct constituency. The IBA Rules on the Taking of Evidence are an international arbitration instrument, designed to be adopted by parties or tribunals across jurisdictions and legal traditions, and are commonly referenced — whether formally adopted or used as informal guidance — in DIAC and other regional institutional arbitrations. The CIArb Protocol is a professional body's guidance specifically addressed to the conduct of party-appointed expert witnesses in arbitration, reflecting the institute's broader remit across arbitration practice generally. The RICS Practice Statement is a chartered surveyor's professional body instrument, mandatory for RICS members under its Rules of Conduct, addressing the surveyor's conduct as an expert witness across any tribunal, not arbitration specifically.
None of these three is, by itself, automatically the governing standard in every GCC construction dispute. Which applies — and with what force — depends on the specific tribunal's rules, any procedural order the tribunal has issued, the parties' own agreement, and, where the expert is a chartered surveyor, the expert's own professional obligations regardless of what the tribunal formally requires.
Where the substance converges
Despite their different origins, the practical content of these three frameworks converges heavily on the core principles this series has worked through:
- An overriding duty to the tribunal that takes precedence over any obligation to the instructing party
- A requirement for the expert's evidence to reflect independent, genuinely held professional opinion
- Clear separation of fact, assumption, and opinion within the report
- Disclosure of the substance of instructions received
- A prohibition, or strong disfavouring, of conditional or success-based fee arrangements
- An expectation that experts will engage constructively in meetings with opposing experts to narrow issues in dispute
For a practitioner who has internalised the principles worked through elsewhere in this series, compliance with any one of these frameworks tends to produce a report and a process that substantially satisfies the others as well. This convergence is not accidental — each framework has developed, over time, in response to the same underlying concern: preserving the genuine independence of expert evidence in adversarial proceedings.
Where they diverge, and how to handle it
The frameworks diverge more in structural detail and specific procedural mechanics than in underlying principle. Differences can arise around:
- The precise content requirements for a written report (the IBA Rules specify particular elements under Article 5; the RICS Practice Statement specifies a somewhat different, more detailed list under its own PS 5)
- The specific wording expected in a statement of truth or declaration
- The procedural mechanics around single joint or tribunal-appointed experts, which vary depending on the institutional and jurisdictional context
- The treatment of dual advocate-expert roles, which the RICS framework addresses in some detail and which has no direct equivalent in the IBA Rules
Where a tribunal's own procedural order specifies a particular framework or set of requirements, that order should generally take precedence for the purposes of the specific proceeding. Where more than one framework is potentially relevant — for example, a chartered surveyor giving evidence in a DIAC arbitration where the IBA Rules have been adopted — the practical approach is to treat the frameworks as cumulative rather than as competing: satisfy the most detailed and most stringent requirement wherever they diverge, since doing so will generally satisfy the less detailed requirement as well.
Why this matters for lawyers instructing experts
For instructing counsel, the practical takeaway is to be explicit, at the outset of the engagement, about which frameworks are expected to govern the expert's conduct — the tribunal's own rules or procedural order, any institutional rules formally or informally in play, and any professional body obligations the expert independently carries as a matter of their own qualification. Leaving this unaddressed and assuming the expert will simply "know what's expected" is a common and avoidable source of friction later, particularly where an expert's own professional body imposes requirements — around fee structure or declaration wording, for example — that go beyond what the tribunal's procedural order strictly requires.
A converging international standard
The broader trend across these frameworks, and across GCC arbitral practice more generally as institutions like DIAC and arbitrateAD continue to modernise, is toward a genuinely international standard of expert evidence — one increasingly consistent regardless of which specific instrument a tribunal happens to reference. Practitioners who build their practice around the underlying principles common to all of them, rather than treating compliance as a box-ticking exercise against a single named framework, are best placed to meet whatever specific requirements a given tribunal or dispute ultimately imposes.
Part 18 shifts focus to a practical audience: contractors and engineering businesses facing a dispute for the first time, and how to go about choosing the right expert.