Expert witnesses are required to make clear which facts are within their own knowledge, list their sources and say when a question or issue falls outside their expertise. In a recent case, an expert witness was criticised for failing to do so.
Engie Fabricom (UK) Ltd v MW High Tech Projects UK Ltd was a claim in the Technology and Construction Court. The issue was whether work done at a plant was 'waste generation' (as the claimant alleged) or 'power generation'. The significance of this was whether the parties had any right to refer a dispute to adjudication and whether the adjudicator's award could be enforced.
The claimant relied on expert evidence from a chartered engineer and consultant in waste and energy. The defendant relied on an expert in energy pricing. He was not an engineer and did not have expertise in waste management or energy from waste industries. His report, as served, included information gained from Wikipedia and other websites. It made no reference to those sources.
The judge was highly critical of what she regarded as a breach of the expert's duty to the Court. First, an expert witness is required to make clear which facts stated in the report are within the expert's own knowledge (CPR Practice Direction 35, para 3.2). Secondly, expert witnesses should make it clear when a question falls outside their expertise (CPR Practice Direction 35, para 2.4).
She 'deprecated' the failure to comply with the expert's duties. The judge added: "I accept that this was not done with the intention of misleading the Court but it could have been avoided easily by following the practice direction."
So the moral of the story is: make sure you understand and comply with your duties as set out in CPR 35.
A reminder of the relevant parts of the Practice Direction is below:
2.4 Experts should make it clear:
(a) when a question or issue falls outside their expertise…
PD 35.3.2 says:
An expert's report must:
(2) give details of any literature or other material which has been relied on in making the report…
(4) make clear which of the facts stated in the report are within the expert's own knowledge…
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