What is an Expert Witness
You may have heard the term expert witness before but are unsure of the details or intention behind the term. They sometimes appear as characters in a television courtroom drama, which does suggest how the role plays out. However, we’ll provide details in this article that go beyond the drama and get into the facts.
The article explains the role of an expert witness, who can be one, how much experience they should typically have, and how impartiality impacts what they do. It also explores a useful example involving water safety and Legionnaires’ disease.
A version of this article outlining the role of an expert witness and what they do about appeared in Legionella Control International’s newsletter. To get it in your inbox, sign up for free here.
How does an expert witness differ from a regular witness?
Court cases involve witnesses to the event that occurred. For example, someone might have witnessed a robbery or other event that has led to someone being charged with a crime. These witnesses provide an account of what they saw, giving the facts as required.
An expert witness can provide facts, but they are engaged to provide their professional opinion about certain aspects of a case. For example, someone might be accused of the murder of an individual whose body was found in a decomposed state. An expert witness working as a pathologist might be called to court to give their opinion on what the evidence found on the body suggests.
An expert witness can be called by the prosecution and the defence, with each side calling in their own expert witness to support their argument. However, in each case, the court must allow someone to act as an expert witness. They cannot be called in if permission is not given.
Who can be an expert witness?
Anyone with relevant experience in their field can be an expert witness. For example, let’s assume there is a court case relating to an outbreak of Legionnaires’ disease. Several people fell ill due to the outbreak, and some have died. Investigators have identified the building where the outbreak occurred, and those responsible for managing the building have been taken to court.
In this case, an expert witness might be requested to give their expert opinion on the management of the water systems within the building and whether this was sufficient to keep people safe. This is an example whereby those dealing with the court case are not expected to have detailed knowledge of Legionnaires’ disease beyond what they’ve read or heard about in the news. Furthermore, they won’t know how legionella bacteria is spread, nor how they can be prevented from doing so, to protect against an outbreak of the disease.
Cases like this show how those prosecuting or defending people in court will not have the required knowledge, information or expertise to help support their case. They must seek information from an expert witness to help in this way. Lawyers are experienced in dealing with all manner of cases and arguing for their clients but cannot be expected to know everything about all walks of life to do so. Thus, the role of an expert witness often comes in useful.
Exploring an example involving water safety and Legionnaires’ disease
Let’s go into a little more depth with an example of where an expert witness might be useful to a case involving poor water safety at a building. One common source of Legionnaires’ disease outbreaks is that of cooling towers. If legionella bacteria are allowed to spread in the water supply serving the towers, it can easily escape via water vapour (an aerosol) coming out of the towers – this aids the cooling process. In turn, this vapour can be inhaled by anyone in the vicinity – even those outside the premises using the cooling towers.
Most people can easily understand this premise, but they would not be able to understand how cooling towers work. They would have no knowledge of the inner workings of a cooling tower, how it can lead to legionella spreading throughout the water system, or what processes should be in place to keep people safe. Therefore, it would be difficult for a layperson to understand how an outbreak could be prevented by those responsible for the maintenance and safe running of the cooling towers.
However, if an expert witness is called in to testify, they can explain how these towers work and what must be done to ensure they are safe. With experience in water safety, the control of legionella and the tasks that must be done to maintain safety, they can explain what those in charge should have done but did not. They can present facts to the court after going over the documents relating to the case, but they can also present their own opinions – something regular witnesses cannot do.
How much experience should an expert witness have?
Clearly, they should have more experience and knowledge than that of a layperson. However, several sources suggest that an individual should possess between 10 to 15 years’ experience at a minimum in the relevant area of interest. If they’ve been practicing their craft or specialism for much longer, they may well be seen as a more valuable expert witness. They may have seen a wider range of scenarios and therefore have far more knowledge to use when addressing a court and answering questions.
The importance of impartiality
This may seem unusual as an expert witness will typically speak on behalf of either the prosecution or the defence. Indeed, some cases have occurred whereby the court has allowed expert witnesses to act for each party. This means one witness will act for the defence and another for the prosecution. Of course, this also means the two expert witnesses will give differing opinions on what occurred.
So, where does “expert” impartiality come into it?
The bottom line is that all expert testimony should be backed by science or knowledge. An expert witness is the only person who can provide opinions on what occurred. However, those opinions are supported by experience, facts, and knowledge that laypeople will not have access to.
It is always vital, though, for an expert witness to remain impartial throughout a case. They should not provide their services if they do not feel they can be impartial. Their duty is to the court and not to either party involved in the case, even though they will be invited to provide their services by one or other party. No conflict of interest should exist either.
Providing access to expert witnesses
If you are seeking an expert witness in relation to a legionella or water safety case, we can provide the necessary services. Get in touch to find out more today… contact us.
World leading legionella risk management specialists
The water safety specialists at Legionella Control International help employers and those responsible for the control of legionella and other waterborne pathogens in the workplace manage their water risks to ensure regulatory compliance is achieved and then maintained to keep people safe from harm.
Our senior consultants provide specialist expert witness and litigation support services in matters relating to Legionnaires’ disease and the management of legionella in the workplace.
Our expert witness services encompass a range of technical, scientific, environmental and engineering subjects directly associated with Legionnaires’ disease and the management of legionella risks within the built environment.
If you would like to speak with one of our legionella specialists about our expert witness services call us today on 0330 223 36 86 or contact us here …
