What is the role of a Psychology Expert Witness?
The role of a Psychology Expert Witness is to provide a court or tribunal with specialist information which legal professionals would not be able to supply. It is important to make it clear that the duty of an Expert Witness Psychologist is to the Court and not the instructing party(ies) i.e. the solicitor(s) or client(s). In addition to individual Expert Witness Psychologist the definition was extended to include “Expert Teams”, as part of the 2010 extension to the Civil Procedure rules. This was in recognition of fact that some cases may require teams of professionals from different disciplines to work jointly to produce a medico-legal report.
Psychology Expert Witnesses, like all other type of Expert Witness, are different to “ordinary witnesses” as Expert Witnesses are permitted to provide an opinion in a case as opposed to simply stating the facts. To enable the Court to assess the reasons behind the Expert Witness Psychologist’s opinions they must supply the Court with the necessary information that lead them to those conclusions. In addition to this, the opinion of the Psychology Expert Witness must be both relevant, as deemed by the “probative value” of that evidence, and admissible.
It is unusual for Expert Witness Psychologists to give an opinion about how a person without any mental health difficulties would react in certain situations or about the truthfulness of a person’s statement or evidence. However, under certain circumstances, such as those involving possible malingering or when video and interview evidence given by a person conflict or matters concerning the reliability or veracity of a child’s testimony. Under these circumstances a Psychology Expert Witness can provide an opinion based upon best practice for those situations such as the use of evidence based and standardised psychometric tests.
One important distinction to draw is that Expert Witness Psychologists are not allowed to give an opinion on a question of fact in the case, that is being considered by the judge or jury e.g. a Psychology Expert Witness in civil family cases cannot make suggestions as to the best placement of a child or confirm if an alleged case of abuse or neglect took place, as this is for the judge to decide.