Expert witnesses are those that provide evidence to assist the court when the court decides the outcome of cases. The difference between a normal witness and an expert witness is that they can provide opinion based on their experience and expertise to the court whereas normal witnesses can only give evidence of what they themselves know within the process.

What is a Medico-Legal Expert Witness?

If a claimant (the person who has been involved in an event that causes them injury), makes a claim for compensation against a third party, they will need evidence. Some of that will be factual evidence, pictures of their car after a collision, evidence from people who saw the event. If however they have suffered injuries where documented in their patient records (either at the hospital or their GP) it may be important that someone with specific knowledge and experience interprets both the details of the injuries, their extent and the likely consequences of them. This is called in the court a “Condition and Prognosis Report” and even in “minor” injuries, this must be obtained usually by the patient’s legal representative.

If there is a dispute as to how the injuries were obtained, the legal representative will call on non medico-legal experts such as crash investigators or Health and Safety experts who will review the reasons for the injuries. 

If the patient (or claimant) considers they have suffered harm due to medical treatment either a late diagnosis or a complication of a procedure or treatment, then their legal representative will instruct one or more medico-legal expert witnesses to provide evidence for them to take the claim forwards. This type of evidence is normally called a Breach of Duty report and a Causation report. 

In addition often a different medico-legal expert will provide a report on the extent and consequences of the harm that has accrued the same as in the other circumstances that cause injuries.

What a Medico-Legal Expert Witness Would Provide

A medico-legal expert witness would be expected to provide evidence based on their knowledge and experience in a professional capacity. They would review evidence from documents and verbal witness evidence and using them, provide an opinion.

The medico-legal expert must be aware that while they rely on evidence to provide their opinion they must never assume that the evidence they initially are presented with, is not in dispute and indeed if they identify a conflict between different sources of factual evidence they must not decide on which his correct. Factual decisions are a matter for the court and an expert must not advocate for a particular version of the fact. This has clearly been recorded in a recent case Muyepa and MoD.

Although in most circumstances, and specifically in medical negligence cases, an expert witness can be appointed by only one side involved in a claim or dispute. In some circumstances they can be appointed by both sides jointly or indeed by the court.

The expert witness must provide a written report on their findings and give an opinion which must be unbiased. Such a report will make up part of the evidence when assessing the validity of a claim. When commissioned by one side in a dispute or claim, a medico-legal report must indicate on what evidence their opinion is based and whether it supports the claim or not. It must also contain details of the extent and potential duration of the injuries. Plus how the client’s life is going to be affected. An expert witness may also recommend any further medical investigations or treatment required. All of this will be based on their personal expertise as well as any relevant medical studies.

Giving Evidence

If a case proceeds and if it is not resolved by the claimant and the third party (who both often have medico-legal experts with differing opinion) and if there is still a dispute about the medical evidence even after medico-legal experts in similar disciplines have met and narrowed their differences, the matter will end up before a judge in court.

At this time the medico-legal expert will give evidence under oath or affirmation before the court and will be cross examined on their opinion by a barrister.

It is important when being cross examined to answer the question that is put to the medico-legal expert honestly and such evidence must be expressed in terms that a non-medical person, such as the Judge can understand. It is important in court that the medico-legal expert must not give evidence for issues outside their own particular sphere of practice and should explain why they cannot answer such a question if posed by the barrister or preface any answer that it is given in general terms and not with specific expertise.

If possible the expert witness should be able to back up their opinion by reference to standards of practice relevant to the incident in question and if possible National guidelines.

Prior to giving evidence the expert will have their evidence tested in a conference with the barrister appointment by the party who has instructed the expert and this can be a useful guide for the expert about the areas of contention and the possible questions they will be asked if they have to give evidence. A good medico-legal expert should never worry about their evidence being challenged in conference as it is better for it to be challenged there than in the witness box where some medico-legal careers have come to an abrupt end after criticism in a judgment of their evidence and performance.

Who Can Be a Medico-Legal Expert Witness

Medico-legal expert witnesses can be drawn from whichever section of the medical profession that is relevant to the case. Therefore, they can include nurses, physiotherapists, physicians from all branches of the profession. The expert witness will be called upon to provide opinion evidence in relation to the cause and types of injuries or the standard of care of the patient and the short-term and long-term care and future impact of medical conditions which relate to their particular field.

Conflicts of Interest

Finally, an expert witness must not have a conflict of interest or indeed a possible appearance of a conflict of interest. If an expert witness has previous personal or professional involvement with the claimant or defendant or anyone involved in the care of a patient in a clinical negligence case, they should declare it as soon as they are aware of even the potential of such a conflict of interest. Again it is embarrassing if such a conflict of interest only becomes apparent when the medio-legal expert is giving evidence in court and this can quickly become a fatal blow to their instructing party’s case.