An expert witness (EW) is an expert who uses their knowledge, training and experience in a specific area to help assist courts and other bodies to understand issues in legal cases so that they reach a sound and just decision. Expert witnesses are typically required in situations where an evaluation of the issues requires technical or scientific knowledge that only an expert in that field is likely to have, such as in cases relating to; loss of earnings, insurance claims, severe injuries, degree of sanity, environmental issues, intellectual property and so on.
Expert witnesses may have a variety of roles, including:
- Acting as an expert advisor where advice is provided but the expert’s opinion is not put before the court.
- Acting as a shadow expert where the advisor works ‘behind the scenes’ in a court claim.
- Acting as an expert witness proper or party-appointed expert when the expert is contracted by one party with the aim of providing an opinion to the court.
- Acting as a single joint expert where the expert is instructed by all parties involved.
- Acting as a lead expert when a complex claim requires multiple experts.
- Acting as an assessor, introduced by the Civil Procedure Rules and appointed by the court as an expert.
The opinions provided by the expert witnesses are described as ‘expert evidence’ and will often include; factual evidence, explanation of any technical terms or topics, and opinions based on the facts of the case.
 Qualities of an expert witness
An expert witness must be independent and must not be swayed by the party paying their fee. Their role is governed by the Civil Procedure Rules.
They should have:
- A detailed knowledge and experience of the subject matter.
- Good analytical reasoning capabilities.
- Good communication skills.
- Capability of adapting to new evidence.
- The ability to think clearly during cross-examinations.
- A confident manner, especially during court appearances.
- Good understanding of the variety of dispute resolution procedures.
Guidance has been produced for both expert witnesses and individuals who instruct experts in the Civil Justice Council publication Protocol for the Instruction of Experts to give Evidence in Civil Claims, published in 2005 and amended in 2009.
The construction industry involves long-term transactions with a high degree of uncertainty and complexity, and it is impossible to resolve every detail and foresee every contingency at the outset. As a result, there are frequent disputes, claims, court proceedings and alternative dispute resolution proceedings. In 2013, the National Construction Contracts and Law Survey, found that 30% of firms had been involved in at least one dispute in the previous 12 months.
This means that those involved in the construction industry may require the services of expert witnesses, or where they have particular expertise themselves, may offer services as an expert witness.
Typical cases include:
- Compulsory purchase orders.
- Contractual disputes.
- Planning permissions.
- Construction defects.
- Design defects.
- Professional negligence.
- Insurance claims.
 Related articles on Designing Buildings Wiki.
- Alternative dispute resolution.
- Alternative dispute resolution legislation.
- Civil procedure rules.
- Contract claims.
- Construction disputes.
- Delays on construction projects.
- Dispute resolution board.
- Expert determination.
- International research into the causes of delays on construction projects.
 External references
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