Expert witnesses: Expertise is not enough

Author: Digby Hebbard

This article was published on Construction News on 31 August 2016.

Poor performances by expert witnesses have been highlighted in several recent cases, so how can you ensure yours are up to the job?

In construction disputes, the law is often only half the story.  The complexity of construction projects – and the issues which commonly arise – often mean that expert opinion is required to support parties’ positions and, in turn, help courts and tribunals reach a decision. Indeed it would appear now to be in only exceptional cases that experts are not required.

Experts’ evidence

Experts involved in construction disputes may give evidence on many matters, such as civil engineering, ground conditions, delay, workmanship, causes of defects, the performance of the professional team and quantification of losses. Expert evidence is typically given in written reports and joint statements, and experts may be subject to cross-examination if the dispute reaches a trial or hearing.

Experts play a critical role in construction disputes – cases may stand or fall on their performance. It is in the parties’ interests to carefully select and manage experts, to ensure their evidence is supportive of their position.

Court criticism

In several recent cases, instances of poor performance by experts have been highlighted by the courts. By way of illustration, in relation to expert reports, the courts have criticised experts where they:

  • failed to keep their opinion to matters within their expertise: for example, by commenting on the legal issues;
  • ignored, or selectively presented, evidence which was adverse to their client’s interests;
  • formed conclusions which were unsupported;
  • accepted facts given by lay witnesses, without interrogation;
  • cross-referred, with approval, to the reports of other experts of different disciplines; and
  • permitted their reports to be substantively redrafted by lawyers, thereby calling into question the expert’s integrity and independence.

Further, in relation to cross-examination, the courts have criticised experts where they:

  • offered no reasonable explanation for discrepancies between their observations and conclusions;
  • refused to acknowledge that some of their conclusions were wrong, notwithstanding clear contradictory evidence; and
  • inappropriately answered questions.

Although possibly extreme examples, they demonstrate that despite the prevalence and importance of experts in construction disputes, considered deliberation still needs to be given to the selection and appointment of suitable experts to avoid these sorts of situations.

Failing to do so may mean that a party’s expert is perceived to lack credibility in the eyes of the decision-maker and which may have catastrophic consequences on the prospects of that party’s position being accepted.

Think before appointing

In practical terms, it is suggested that parties to construction disputes consider certain points carefully when instructing experts.

Firstly, it is advisable to review the expert’s background for experience in giving evidence or acting in dispute resolution – particularly in cross-examination and ‘hot-tubbing’ (a method increasingly favoured by the courts) – it would be risky indeed to engage an expert that hasn’t been through cross-examination.

Many of the failings mentioned above appear to arise from inexperience of the dispute resolution process. Once an expert has been instructed, the client should clearly define the scope of the matters on which the expert’s opinion is required, to ensure that there is no ambiguity as to what their report should focus on.

On completion of a report, it is also vitally important to ensure that, as far as possible, the expert’s conclusions logically follow their analysis, and are based on a recognised branch of knowledge within their area of expertise. The expert must also be seen to have retained full ownership of their report.

Digby Hebbard, Partner, Fladgate LLP (



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