The Role of Expert Witnesses

What is an Expert Witness?

An expert witness give expert evidence in court proceedings based on their specialist knowledge gained through education and training, qualifications and experience. The testimony of an expert witness will be such that the court can rely on their opinion about a particular fact or issue within their scope of expertise.

When is an expert witness employed?

Expert witnesses are needed in very many court cases, such as personal injury and medical negligence cases, and cases involving allegedly defective items. Forensic accountants are often relied on in financial remedies cases on divorce, and intellectual property disputes may require expert witnesses to help the court determine if there was any infringement of a party’s trademark, patent, or copyright.

Sometimes, the judge will request the assistance of an expert witness to help the court evaluate issues, or to acquire more knowledge on the matter under review. However, no expert witness evidence or report is permitted without the court’s permission.

What is the role of an expert witness?

Under the Civil Procedure Rules (CPR), an expert witness must be independent and must address their expert report to the court having jurisdiction over the case (the CPR apply only to the courts in England and Wales.

The parties can agree to jointly instruct an expert witness, particularly if the amount at issue in the case is relatively small. This saves the cost of each party having to pay for their own separate expert witness, but the parties must be in agreement as to which expert is to be instructed.

The duty of an expert is to help the court on matters within their expertise – and this duty overrides any obligation to the party who instructed expert (and, indeed, the party who paid the expert). An expert witness must have a high sense of honesty and integrity: perjury, or the giving of false statements in court or in subscribed documents, is treated very seriously by the courts. An expert therefore has a duty to be sufficiently knowledgeable of the CPR, the management of time limits, management of cases, and so on.

An expert must be objective in giving their expert opinion at all times. This means their opinions should be based on factual observations, and must not serve to deliberately favour a particular party in the case.

An expert witness is required to include in their final report a clause that they understand their duty to the court. They must also state that they have complied with and will continue to comply with all such duties, and are aware of the relevant requirements under the CPR. The report must also comply with other procedural requirements set out in the CPR, including stating the substance of all material instructions on the basis of which the report was written.