Expert witness immune from negligence action brought by former client
December 12, 2016
In a recent summary judgement decision, the Ontario Superior Court upheld the principle that witnesses are immune from liability for their testimony given at trial. This particular case had an interesting twist in that the plaintiffs brought an action against their own expert witness when the trial at which he testified did not go their way.
The plaintiffs hired the defendant business valuation expert to prepare a report with respect to the value of the shares of a company in which they were shareholders. The value of the shares was a central issue in the plaintiffs’ claim against the company and its majority shareholder.
During the trial, one of the plaintiffs gave opinion evidence as to the value of the shares. Although he was an experienced real estate broker with considerable knowledge about the type of property owned by the company, his evidence, as an interested party, was deemed worthless. Unfortunately, the consequences for the plaintiff did not end with his own testimony. The plaintiffs’ expert made reference to various aspects of the plaintiffs’ “findings” in the expert’s technical report. As a result, the trial judge rejected the plaintiffs’ expert’s evidence in favour of the defendants’ experts and awarded a far lower figure in damages than the plaintiffs were seeking.
As a result, the plaintiffs commenced a separate action against the expert and his appraisal company for negligence and breach of contract. They sought damages largely representing the difference between the share value found by the trial judge and the value ascribed to the shares by their expert.
It is well-established that witnesses and parties are entitled to absolute immunity from subsequent liability for their testimony in judicial proceedings so as to promote the full and free participation of witnesses unhindered by fear of retaliatory lawsuits. Although the principle has mainly been applied to witnesses adverse to the party suing, the Court in this case saw no reason why it should not apply equally to a party’s own expert witness. This protection promotes the policy that all experts must be objective and not become a “hired gun”.
The Court was also concerned that allowing parties to sue their own experts meant allowing parties to relitigate their case when they are dissatisfied with the result. In granting the expert’s motion for summary judgment, the court held the principle of finality strongly supported the application of the common law doctrine of witness immunity in this case.
This is not to say that a party has no recourse when they are dissatisfied with the performance of their expert. A party is free to dispute payment of the expert’s fees as the plaintiffs did in this case as well. However, an expert’s testimony cannot form the basis of a separate suit amounting to a de facto appeal of a negative trial decision.
Paul v. Sasso et al., 2016 ONSC 7488
