What is an Expert Witness?

An expert witness or professional witness is someone who by virtue of education, training or experience is believed to have specialised knowledge in a particular subject beyond that of the average person, sufficient that others may officially and legally rely upon the witness’s specialised (scientific / technical) opinion about an evidence or fact issue within the scope of his/her expertise.

When expert evidence is wanted in a court of law, it’s time to call an expert witness. In many trials, it is the careful considered evidence they give that can ensure a just outcome.

When in court, the expert methodically presents opinion evidence based on evidence of fact. The initial report which the expert witness also prepares, would be written within a specified time scale in compliance with specific legal guidelines.

Their experience can offer an opinion on a matter before any court. He or she should be able to present highly technical matters in a language which can be easily understood by the average person. The expert must be able to justify his or her professional opinion under various cross examinations.

The primary function of an expert witness is to engaged his/her independent expert opinion based on the information that is provided. An expert can be instructed in different capacities for example at arbitrations, tribunals and litigation.

Types of Expert Witnesses in England & Wales

Party Appointed Expert (PAE): Is appointed and instructed by one of the parties in the dispute. The duty is to assist the court on the matters within his/hers expertise and this duty overrides any obligation to the party from whom he/she has received instructions or by whom he/she is paid.

Single Joint Expert (SJE): Is appointed and instructed by the parties involved in the dispute. The duty is to assist the court on the matters within his/hers expertise and this duty overrides any obligation to the parties from whom he/she has received instructions or by whom he/she is paid.

Expert Adviser (EA): Is appointed by one of the parties to advise them in the dispute. This type of expert is not covered by the civil procedure rules and does not have a duty to the court and will not normally give evidence.