The role of the expert can be integral to court cases, proving informed evidence and argument... | DDLS Issue 73

Why It Pays To Instruct A Trained Expert Witness

The role of the expert can be integral to court cases, proving informed evidence and argument. 

It can be very tempting to carefully select an expert who endorses your case.  However, care is needed.  The role of the expert witness in relation to court cases is defined by very specific protocol and a failure to observe this can prove detrimental to the strongest case.

In almost every other element of work that the expert undertakes, there is a degree of advocacy, in that I am commissioned, in part, to represent my client’s interests.  However, as an expert witness, my duty is to the court, even though I have usually been instructed by one of the parties. 

Any bias in the expert's report is prone to be highlighted by the QC for the other side, and this could undermine the merits of the case. One of the key areas where care is needed relates to facts and whether they are known or assumed.  The expert needs to be able to separate these and attribute weight accordingly.  Otherwise, a case may be built on wrong evidence.  This is more than semantics over wording. 

Unless I know something to be a fact, I need to establish that I am assuming it.  If my client informs me of an event, there is the risk that, without independent evidence, they could be wrong.  The caveat that I am assuming they are correct places the issue in context. A good QC will look for weaknesses such as this, and focus questions here.  Otherwise, good work can be underdone by presenting an assumption as fact.

There are facts and opinions.  These need to be treated separately.  Often the court is seeking my opinion.  This needs to be presented clearly, in its own section and based on the evidence.  I once read the report of an expert who provided their own character appraisal, suggesting that one party, whom they had never met, was not a reliable witness, and thus discounting their evidence.  I seek to avoid such wording. It is for the barrister to deal with this element. I focus on the merits of the evidence. It is also important to stay above the emotions of a case. 

I frequently work on boundary disputes, which are often associated with a breakdown in relations between two parties.  It is integral to the case to operate away from this emotion and to calmly navigate the path of clear facts and opinions.  In truth, this can be a challenge.  I used to be a tree officer for a local authority and appreciate the emotions that can develop when trees subject to a Tree Preservation Order have been damaged or felled. 

I have represented both parties in different prosecutions and have seen otherwise strong cases thwarted when the evidence has not been subject to sufficient rigour.  In one notable case, the prosecuting authority based their argument on the defendant confirming that he had felled the trees, and didn't explore whether the work could have been exempt!

My training included the emphasis that the expert needs to comment only on their own area of expertise.  This can require discipline, as instructing parties can ask questions away from this. 

One of my specialisms is tree safety, and I have been asked to explore if weather was a factor in tree failure.  One has to be careful not to try to become a meteorological expert in this but to place supporting evidence in the correct context. Finally, as I mentioned earlier, my duty is to the court. 

I cannot be a hired hand.  This was drilled into me during my training with Bond Solon.  When doing my work, I try to picture myself sitting down with both parties and explaining the situation to them.  My report should be the same whether I am instructed by either party or as a Joint Single Expert. 

The courts seek the thoughts of an expert and assume that this person is familiar with protocol.  A trained expert is and is thus better placed to correctly present the evidence.  As a CUEW, I am required to remain up to date on legal issues and protocol, ensuring that this element of a case is in safe hands. Mark Chester, Cedarwood Tree Care