Expert evidence is commonplace in many types of cases ranging from boundary disputes, professional negligence, and personal injury all the way through to custody and divorce actions and obtaining expert evidence is an important part of preparing a case for court. Expert witnesses charge substantial fees and so it is crucial the right person is instructed for the right reason. There are plenty of people who are willing to hold themselves out as experts in all manner of disciplines so identifying an appropriate expert is not always easy.
According to Lord Neuberger and expert witness is, “A witness who gives opinion evidence to the court on technical, scientific or other specialist issues, which the court considers appropriate for expert evidence and any such evidence should represent the expert’s honest independent opinion based on his knowledge and experience.”
The Supreme Court in Kennedy v Cordia (Services) Ltd  CSIH 76 set out four considerations:
- Whether the proposed skilled evidence will assist the court in its task;
- Whether the witness has the necessary knowledge and experience;
- Whether the witness is impartial in his or her presentation and assessment of the evidence; and
- Whether there is a reliable body of knowledge or experience to underpin the expert’s evidence.
The expert witness must be giving evidence on a subject which the sheriff would only be able to understand with the input of the witness’ expertise. The Sheriff is not interested in hearing the expert’s opinion on matters that they are more than capable of assessing. For eg, two child psychologists gave evidence in a case concerning the relocation of the parties’ children and whether this was in the children’s best interests. The Sheriff decided not to admit the expert evidence as she felt that the courts were well placed to determine this for themselves.
Consider whether the expert witness you want to instruct has the relevant experience and qualifications. The contractor you employ to rip out a faulty bathroom isn’t necessarily best placed to comment on the skill with which the original bathroom was installed. The impartiality of their evidence will also be open to challenge.
It is important that the expert witness is provided with all of the relevant factual material in a case and this should include not only that material that supports your case but also material that points in the other direction. The questions that should be asked should not be the very questions which the court is asked to determine. For example, when instructing an expert opinion on something like professional negligence, determining the issue of causation is the court’s job and they won’t be impressed with an expert who tries to tell them what their decision should be.
There is a lot to consider when instructing an expert witness but get it right and that expert may win you your case – and recovery of their fee from your opponent!