Expert evidence and construction claims

Author: Digby Hebbard

This article was previously published in ‘Construction News’ in December 2016.

Key points:

  • Expert evidence is required in most construction and engineering disputes
  • Experts will usually prepare written reports and may be cross-examined
  • Expert evidence can determine the outcome of construction disputes
  • There have been some recent examples of poor expert evidence performance being harmful to party’s cases
  • Careful consideration and deliberation are always required in relation to the selection and management of experts at the outset

Construction and engineering projects are inherently complex. Highly specialist skills are required to design, programme, value, construct and monitor projects.  It follows that disputes arising from such projects will inevitably require consideration of the performance of these technical and practical skills.  For example, does that element of the design satisfy the employer’s technical requirements?  Was the tunnelling on the critical path of the programme?  Was cracking in the concrete caused by workmanship?  Was this leak caused by a failure to maintain the facility?  What additional costs have been incurred as a result of a delay?

These sorts of issues normally go to heart of disputes arising in connection with construction projects. As such, these issues are material (and often requisite to) the determination of liability and quantum.  The same issues are also (usually) only able to be addressed and dealt with by independent and objective technical specialists, otherwise known as expert witnesses.

The role of experts therefore should not be understated – disputes are often decided purely on the basis of matters within the exclusive realm of technical experts. Indeed, it would now appear that it is only in exceptional cases that experts are not required.

It is submitted that the selection and management of experts should be an essential strategic consideration for parties likely to be involved in construction disputes. Inadequate investment in this may prejudice a party’s position and this has been demonstrated in some recent decisions of the courts.


The procurement and delivery of construction and engineering projects can require input from multiple technical disciplines. When it becomes necessary in the context of dispute resolution to consider the performance of such input, for example, as a contributing factor to cost or time overruns, parties will engage experts to give evidence.

Construction project disputes will often involve, for example, geotechnical, civil and structural engineers, as well as architects, delay analysts and quantity surveyors. Expert evidence is typically given in written reports and joint statements (in conjunction with other parties’ experts), and experts may be subject to cross-examination if the dispute progresses to trial or a hearing.

In broad terms, the role of experts in dispute resolution is to act independently and assist the court, tribunal or arbiter to reach a view on the particular technical issue. Parties’ experts may agree or disagree on the technical issues and in the event of disagreement, the court or tribunal will determine which expert evidence it prefers. As intimated above, a party’s position could stand or fall subject to the performance of its expert.

Careful selection and management of expert witnesses is essential in all cases. Put shortly, parties should ensure that experts are appropriately qualified and experienced in the relevant field; understand and comply with their obligations of independence and perhaps most importantly, understand their role of giving evidence before the courts and tribunals.

Set out below are some recent instances where experts have been criticised by the Courts, which demonstrate common failings in this regard.

Recent case analysis

Van Oord UK Limited and SICIM Roadbridge Limited v Allseas UK Limited (2015) (“Van Oord”) and the Oscensa Pipeline Group Litigation, Re (2016) (“Oscensa”) illustrate some causes and consequences of inadequate expert witness performance.

Briefly, Oscensa concerned claims by a group of Colombian Farmers in relation to the construction of the Oscensa pipeline in Colombia during the 1990s. The litigation involved a number of highly complex technical issues which required extensive expert evidence on matters including geotechnology, hydrology and financial analysis.

Van Oord concerned claims for delay in relation to the laying of a gas pipeline as part of the Shetland Gas Project.  Relevantly, it was the issue of quantum where the role of the experts was noted in the judgment.

Common to both cases was the Court’s criticisms of the expert evidence. First, in relation to the expert’s reports, the Courts criticisms of the experts included that they:

  • Ignored, or selectively presented, evidence which was adverse to their client’s interests. For example, in Oscensa, one of the experts had omitted certain wording from a written sources cited in his report, which he considered detrimental to the client’s case.
  • Appeared to claim expertise on matters in which they had none.
  • Formed conclusions which were unsupported by their recorded observations.
  • Accepted facts given by lay witnesses, and accepted the client’s case at face value and without interrogation.
  • Cross-referred, with approval, to the reports of other experts and adopting the other experts’ reasoning as part of their own – even although those experts were of a different discipline.
  • Disregarded actual costs incurred by the claimant in favour of ‘made-up’ or calculated rates.
  • Appended documents to the report, which the expert had not read in full or at all.
  • Permitted their reports to be substantively redrafted by lawyers, thereby calling into question the expert’s integrity and independence, and also the expert process as a whole.

Second, in relation to cross-examination, the Courts were critical where the experts variously:

  • Offered no reasonable explanation for discrepancies between their observations and conclusions. In Oscensa, the court noted that this was suggestive of an expert with no litigation experience; or perhaps unconscious bias.
  • Refused to acknowledge that some of their conclusions were wrong, notwithstanding clear contradictory evidence.
  • Admitted their own reports could be confusing or misleading.
  • Made multiple concessions as a result of having failed to critically analyse the claim.
  • In Oscensa, purported to be an expert in a particular field (in this instance, pipeline project management), yet appeared under examination have no relevant expertise or experience at all, such that there “was nothing left [of the expert’s evidence] that could properly be called expert opinion evidence”.
  • In Oscensa, persistently answered questions in a way which advocated the client’s case, even where these were not appropriate answers to the stated questions. This delayed the cross-examination process.

In Van Oord, the court stated that the defects in expert evidence (specifically, that given by the claimant’s quantum expert) rendered it entirely worthless. This left the court with no option but to prefer the defendant’s evidence.

In Oscensa, the court noted that while the various failings in the expert evidence did not render it inadmissible, such failings cast doubt on the experts’ reliability. The court also stated that the ‘presentation’ of expert evidence was of course a separate matter from whether the evidence was right or wrong. However, it is clear from reading the court’s comments in that case that the poor presentation of expert evidence nonetheless made it difficult for the court to make findings of fact.

Although Van Oord and Oscensa possibly demonstrate more extreme examples of expert failures, arguably the criticisms could have been avoided had adequate consideration is given to the selection and management of experts at the outset.  In any event, these cases are useful reference points.

There are subtler ways in which an expert might damage his expert’s credibility, or render his opinion inadmissible. In a Scottish case heard recently in the Supreme Court (Kennedy v Cordia (Services) LLP (2016) UKSC 6) (“Kennedy“), the court considered the report of a health and safety expert which appeared to provide opinion on certain legal matters connected with his technical expertise. The court did not rule that the expert report was inadmissible (because a court could turn its own mind to the legal issues at hand) – but suggested that, in principle, where experts failed to keep their opinions to matters strictly within their expertise, those elements of their evidence may be inadmissible.

In Kennedy, the Supreme Court also noted that expert opinion must be based on a reliable body of knowledge or science – or else may be inadmissible. What constitutes a reliable body of knowledge depends on the subject matter of the proposed evidence. For example, in a matter concerning blasting operations, the body of knowledge may be civil and mining engineering. In Kennedy, the court rejected an argument that health and safety was not a recognised body or science or experience. However, it suggested that there may be more difficult cases in which expertise relied upon may be based on science or methodology which is relatively recent, not widely recognised or yet so developed that it could be treated as reliable. In such cases, it could be difficult to test the quality of expert opinions, or find support for their methodology. Consequently, such evidence might be rendered inadmissible.

Practical advice

It is important to remember that the legal team in a dispute has a duty both to the client and the court/tribunal to properly manage the expert process, so as to ensure the expert’s independence. This point was highlighted by the Supreme Court in Kennedy.

Therefore, where it appears likely disputes may arise in connection with a construction project and expert technical evidence is required, it is suggested that parties:

  • Carefully identify what are understood to be the technical issues. It may not be possible to determine at this stage what specialist field the issue relates to.
  • Make enquiries of potential experts and verify that they are appropriately qualified and experienced in the relevant field and that they have experience of acting as an independent expert in the relevant forum (e.g. arbitration, litigation).
  • Check references from earlier projects and specifically in relation to preparation of expert reports and performance under cross-examination. It would be risky indeed to engage an expert that has not been through cross-examination.
  • Ensure that the expert retains full ownership of the report and investigation (and does not accept the opinions of other witness without interrogating the relevant facts). Significantly, lawyers should not yield to any pressure from clients to steer the expert toward conclusions that might be considered partial.

If parties ignore their expert due diligence and/or discover part-way through the process that an expert is not suitable and should be replaced, they are at risk of “expert shopping” and can be expected to be required to disclose the results of the initial expert’s analysis, which may not always be helpful (refer, for example to Allen Tod Architecture Ltd (in liquidation) v Capita Property and Infrastructure Ltd (2016) EWHC 2171 (TCC) and BMG (Mansfield) Ltd and another v Galliford Try Construction Ltd (2013) EWHC 3468 (TCC).

Finally, the parties should have regard to the scope of the expert’s report and how this might resonate in costs. In Wattret v Thomas Sands Consulting Ltd (2015) EWHC 3455 (TCC) the TCC reminded the parties that witness evidence should be restricted to matters which were strictly necessary to the points at issue. It cautioned against experts providing excessive commentary on unnecessary matters, and noted that adverse cost consequences might be visited on a party that chose to submit such evidence.

Digby Hebbard, Partner, Fladgate LLP (

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