Nick Deal explores a case in which the judge deemed two expert witnesses to have failed to explore every possible hypothesis.
Experts are always reminded by the courts to be objective in analysing the evidence and in arriving at their opinions. So, how should the expert demonstrate this in their written and oral evidence?
The issue was explored in the case of Kent CC V M [2024] EWFC 209 (B), by Her Honour Judge Coffey. The case was highlighted in this year’s Annual Legal Update at the Bond Solon Expert Witness Conference and this article goes into more detail.
The case concerned a four-month-old child (M) with either six or seven fractures. A referral was made to the local authority which subsequently alleged that M had sustained non-accidental injuries.
The judge had before her factual evidence from the parents and the other care givers; evidence from the professionals, medical and local authority; and evidence from a number of expert witnesses.
The court’s approach:
The local authority has the burden of proving the allegation of non-accidental injury; the parents do not have to disprove it, or to identify another cause or to prove their innocence. The standard of proof is the balance of probability.
The roles of the experts and the courts are distinct – the judge makes the final decision as they are able to view the totality of the evidence, often referred to as the ‘wider canvas’. This is important to remember, because the experts can help the court by providing their objective, evidence-based opinions and reasoning; it is for the court then to analyse and assess that evidence alongside all the other evidence in the case. The experts themselves do not decide the case.
Courts, and experts, must be careful to remind themselves of the possibility of an unknown cause. HHJ Coffey cited the judgment of Hedley J in Re R, Care Proceedings Causation [2011] EWHC 1715 (Fam): “there has to be factored into every case which concerns a discrete aetiology giving rise to significant harm, a consideration as to whether the cause is unknown.”
Underpinning that observation is the simple reality that “what may be unexplained today may be perfectly well understood tomorrow” (see para. 5.7 of the current case).
Judge’s observations on the expert evidence:
Experts should therefore keep that framework in mind as they write their reports and as they give evidence in court and are cross examined.
In the judge’s view, the paediatric radiologist, Dr J, had taken a linear approach to causation and had made “avoidable errors which do give the court reason to question whether Dr J reflected comprehensively on the evidence sent to him with an open mind, specifically in relation to lines of potential further enquiry, which is critical in a case where the radiological evidence is pivotal.”
It was potentially relevant to the issue of non-accidental injuries that M had been given Omeprazole. There is no established causal link between the drug and fractures, but it is one avenue which could open up the possibility that the injuries seen were organic rather than inflicted and it was one with which Dr J did not deal adequately.
The judge also commented on the manner in which another expert, Dr C, gave her evidence in the witness box.
She noted that Dr C became “defensive in cross examination”, a process that every expert witness should expect to undergo and one which “rightly and fairly tests a party’s case and an expert’s conclusions”.
It is worth quoting the judge’s comments more fully as this goes to the heart of how the court will assess the weight to be given to an expert’s opinions:
“The concern of the court in relation to these comments is less about the omissions from her reports but more about her apparent unwillingness to take on board the criticism and approach the case with an open mind, particularly given the additional evidence which – as is often the case – was raised shortly prior to or at the trial. Dr C’s evidence is a key aspect to the Local Authority's case and the court is left with the impression that Dr C was unable to move away from her starting position that metaphyseal fractures in a non-ambulant infant are likely to be inflicted, and that M would have been in immediate and obvious distress. This is a complex case medically and the court needs the assistance of the experts instructed to contemplate all hypotheses.”
Where an expert does not engage with the countervailing arguments to a non-accidental injury hypothesis, a question is raised over their open mindedness which in turn has an impact on the impartiality of their evidence.
That can be fatal to the ability of the court to place confidence in the opinion of the expert witness.
In the context of this case, the judge held that the local authority had not established non-accidental injury on the balance of probability as the expert evidence was not conclusive and the surrounding evidence did not support non-accidental injury.
What to conclude from this case?
- Experts should always remember that it is the court that decides the case and that the experts are there to provide their expertise to help the court to make that decision.
- The courts are served by experts who thoroughly consider all the evidence before them and comment on it objectively and comprehensively.
- The courts want the experts to consider all possibilities openly, particularly keeping in mind that the cause may legitimately be unknown – that is a legitimate and helpful conclusion to arrive at, if that is where the evidence takes you.
- Cross examination can be rigorous and challenging – it is vital that experts are ready to undergo that challenge in such a way that their evidence can still stand and be properly taken into account and assessed by the court.
Nick Deal is a barrister and Bond Solon trainer