Get the basics right
Expert evidence of little value if it fails to address the case
No matter how good an expert might be, or how eminent, his evidence will be of little value if it fails to address an opponent’s case. This point was driven home hard by Andrews J in Sally Harris -v- Francis Johnston  EWHC 3193 (QB). The case involved a claim for clinical negligence brought against the defendant consultant neurosurgeon. During the course of surgery, the defendant, using a Cobb dissector, caused injury. The court was asked to determine whether the neurosurgeon’s standard of care had fallen below that to be reasonably expected.
In his report, the defendant’s expert referred throughout to the defendant having used a Cobb dissector. For some reason, however, the claimant’s expert referred in his report to the use of a Cobb retractor, which is an entirely different instrument. In his report, the claimant’s expert had, therefore, proceeded on an entirely erroneous assumption as to how the injury had occurred. He had made no reference to what was pleaded in the defence or the evidence as to what actually happened, ignoring all references to the instrument being blunt – which the dissector is but the retractor isn’t. It was clear from this that, at the very least, he had not read the material before him with the appropriate degree of care or asked the questions one would have expected of him to obtain clarification.
During cross-examination, the claimant’s expert admitted that he should have checked the facts. He argued, however, that he was still able to respond to the defendant’s expert’s report and that, whatever instrument had been used, it had ended up in the wrong place and was indicative of negligence. The judge viewed this as being both intransigent and unhelpful. It is worth noting that this expert had been criticised previously in another case for making factual assumptions without checking their accuracy.
The judge could, of course, have allowed the expert to proceed to respond to the defendant’s points on the grounds that the failings in his report would go only towards issues of his credibility as a witness. In this case, however, Andrews J took the view that the effect of the expert’s failings went far beyond matters of mere credibility. His fundamental misapprehension as to how the injury was sustained meant that the first time he addressed the defence case was in cross-examination, at which point he had attempted to introduce two entirely new hypotheses, of which no mention had been made in his report.
The judge was in no doubt that the expert had failed in his duty under CPR Part 35 and this was made worse by the fact that he had been criticised previously for factual inaccuracy. Under the circumstances, the judge found that he had no option other than to disallow the claimant’s expert’s evidence in its entirety. Instead, the claimant would have to rely on the defendant’s expert evidence which opined that, if the court accepted the defendant’s account that he exerted only gentle pressure to pull away soft tissue which he found to be ‘very tough and fibrous’, then he did not fall below an acceptable standard of care.
Experts must be alert to their duty to use care in checking their facts and to address the facts at issue. If necessary, they should seek clarification. Failure to do so may not only affect their credibility as an expert but might lead to the whole of their evidence being disregarded. On the basis that the failure is indicative of lack of care and breach of duty, it could prove disastrous to the expert personally and the expert’s party, even if the error or misapprehension is less serious than in the instant case.