Late last month, the Sixth Circuit reversed a trial court’s exclusion of expert evidence in a product liability action, despite the discretion generally given to trial court judges to handle evidentiary matters. The case involved allegations that a product defect caused the plaintiff’s injuries while target shooting with his revolver. The plaintiff proferred an expert in the field of mechanical engineering to explain how the alleged defects in the revolver caused his injuries. The expert’s theory, however, contradicted the plaintiff’s own testimony regarding what happened at the time of the accident. Despite the fact that other evidence presented in the case supported the expert’s theory, and the argument that the plaintiff’s recollection may have been faulty, the trial court excluded the expert’s testimony on the grounds that it was not relevant to the facts of the case due to the inconsistencies. The Sixth Circuit reversed, holding that because the expert’s opinion was based on other facts in the case, including other witness accounts and certain physical evidence, and because the expert otherwise used reliable methodology and had sufficient qualifications, there were no grounds for exclusion.
In particular, the Sixth Circuit noted that relevance is not determined by consistency but by whether there is a plausible relationship between the evidence and the ultimate facts at issue. According to the Court, it could be proper for a jury to find for the plaintiff based on the inference that the plaintiff’s own testimony was inaccurate, and the expert’s testimony is relevant to this alternative account of the incident. The opinion clarified that the plaintiff’s testimony as a witness is not a judicial admission, and there is no rule requiring that the legal arguments made by plaintiff’s counsel rely on its truth and accuracy. The Sixth Circuit noted that an expert opinion should be excluded where it “relies on facts that no jury could accept, or relied on the rejection of facts that any jury would be required to accept,” and pointed out that it was critical in this case that the expert’s theory did not contradict the physical evidence, which has to be accepted as plain fact.
The dissent concluded that excluding the expert testimony on relevance grounds was properly within the trial court’s discretion as gatekeeper. In defending the exclusion, the dissent noted not only that admitting the expert testimony would require a degree of speculation that is not demanded of the trial court judge, but also that finding an abuse of discretion where the trial court judge does not entertain this level of speculation “runs the risk of creating a one-size-fits-all standard of expert evidence that makes the relevancy requirement a nullity.” While the dissent was a bit animated, it shows that requiring a finding of relevance for expert testimony that contradicts a plaintiff’s story – as the majority opinion does – really struck a nerve.
A clear takeaway from the decision is that experts may not be strictly bound by the testimony of the parties who proffer them, and attorneys should not be afraid to work past inconsistencies where there is a plausible explanation to build a well-reasoned theory of their case. Of course, it would be best to avoid any inconsistencies in the first place, but in the absence of that luxury, and so long as there is other evidence to support the theory, an expert may still be free to offer an opinion that deviates even from her proponent’s recitation of the facts.